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Scientists at the U.S. National Nuclear Security Administration have called into question the severity of climate risks posed by nuclear war but independent scientists at universities and civilian research agencies say nuclear war could drastically cool Earth’s climate.
October 2025
By Andrew J. Ross
The National Academies of Sciences, Engineering, and Medicine published a consensus study report June 25 entitled “Potential Environmental Effects of Nuclear War.”1 It was authorized by the U.S. Congress in 2021 to evaluate the “non-fallout atmospheric effects of plausible scenarios for nuclear war, ranging from low-quantity regional exchanges to large-scale exchanges between major powers.” Thereafter, the National Academies of Sciences, Engineering, and Medicine convened a committee of scientists with a wide variety of disciplinary expertise to compile and assess the relevant scientific literature on nuclear war’s potential environmental repercussions.

The release of this report presents an opportunity to reflect upon the institutional interests that have shaped the scientific literature on this subject. Initially concerned by the Cold War nuclear arms race, independent scientists at universities and civilian research agencies have been engaged in this form of climate research for more than four decades. Their research finds that nuclear war could drastically cool Earth’s climate and collapse the world’s agricultural systems. Many believe that their work weakens the viability of a nuclear first-strike capability as a credible national security posture. These scientists posit that the environmental aftereffects of even a successful first strike would reverberate to the attacking nation, placing its own survival in jeopardy. They call this nuclear dilemma “self-assured destruction.”
However, institutional interests embedded within the U.S. nuclear weapons complex wield substantial influence over nuclear policymaking. Many nuclear strategists within this complex promote an aggressive nuclear posture premised upon a potential first- strike capability. Scientists who work within these institutions have published studies in recent years downplaying the findings of independent scientists whose research questions the security imperatives of a first-strike capability.
Disagreements among scientists, based upon institutional affiliation, will likely grow more pronounced. Taking a historical view of debates on this subject, however, it is clear how structural incentives have shaped scientists’ judgment of technical uncertainties and societal risks pertaining to the environmental impacts of nuclear war.
Identifying Gaps in the Literature
Since 2023, reports by the National Academies have drawn increased attention to the U.S. Department of Defense’s lack of knowledge about the aftereffects of nuclear strikes. Existing assessments by the department have been limited to the “prompt military effects” of nuclear weapon detonations relevant to tactical operations, such as blast impact and localized fallout. As a result, one NAS report found that “there is a need to improve the understanding of the physical effects of nuclear weapons […] as well as the assessment and estimation of psychological, societal, and political consequences of nuclear weapons use.”2 These assessments have heightened the anticipation for the National Academies’ latest report on nuclear war’s environmental effects.
The new report’s principal aims were to identify gaps in the existing literature and provide a basis of coordination for future research. The study committee broke down research into discrete and sequential steps. To conduct this research, scientists first investigate how and to what degree nuclear detonations and subsequent urban fires might inject particulate matter, especially heat-absorbing black carbon soot, into the upper troposphere and stratosphere, where it would remain above weather systems and take years before precipitating back down to Earth. Second, scientists examine how this highly lofted particulate matter would alter the planet’s biogeochemical cycles, ecologies, agricultural, and socioeconomic systems. The first set of variables determines how nuclear war could reshape the planet’s atmosphere, while the second set establishes how such an altered atmosphere could affect life on Earth.

From these two categories, the committee then deconstructed the study of nuclear war’s environmental effects into six basic subcategories and illustrated how each layer of causation related to the others. These subcategories included: how nuclear weapons might be used; what type of fires might result from nuclear detonations; how massive urban fires might transport aerosols into the atmosphere; how these aerosols might reshape climatic and hydrological patterns; how ecosystems might respond to changes in temperature, solar radiation, and rain levels; and how these new ecological regimes would impact human societies and infrastructures. Each element has complex and interwoven causal pathways, which make deciphering the ramifications of any given nuclear war scenario exceedingly challenging to ascertain with a high level of confidence, the committee asserted.
This intricately constructed framework formed the foundation of the committee’s assessment. Each chapter considered one subcategory, describing its plausible outcomes and identifying “key uncertainties and data gaps” needing further research. Moving forward, the committee judged that the study of the environmental effects of nuclear war would require prolonged financial and technical investments as well as sustained collaboration among scientists operating with multiple, integrated computer modeling programs.
Report Findings and Context
When reviewing the existing literature, the committee concluded that too many uncertainties remained to ascertain how nuclear war scenarios might impact climatic, ecological, and socioeconomic conditions. The panel’s evaluation largely steered clear from directly assigning more credibility to some studies over others, despite disagreements among scientists modeling the environmental outcomes of nuclear war. The existing literature largely agreed that if large volumes of particulate matter from urban fires reached the upper troposphere and stratosphere, then substantial climatic cooling would occur globally. Studies conflicted, however, on whether substantial amounts of soot and smoke would be lofted so high. The committee judged that the ways in which climatic cooling might impact ecosystems, agriculture production, and supply chains required additional study.
The committee acknowledged that nuclear war would have severe, deleterious environmental outcomes and that many of these disruptions would be associated with a climatic cooling effect caused by highly lofted particulate matter. Yet, it found that unknowns persisted as to the degree of cooling and the severity of its impact on communities worldwide. On the whole, the report was a comprehensive but circumspect appraisal of the literature on nuclear war’s environmental aftereffects.
Historically, disagreements on this subject have fallen along the lines of institutional affiliation. Generally speaking, the work of scientists employed at universities or civilian federal laboratories has supported the claim that nuclear war likely would trigger severe climatic disruptions with devastating consequences for the environmental and agricultural condition of nations both targeted and not targeted by nuclear hostilities. Conversely, scientists working within the U.S. National Nuclear Security Administration laboratories, such as Lawrence Livermore and Los Alamos, which design U.S. nuclear weapons, have criticized these findings. They argue that nuclear war is not likely to result in severe climatic perturbations. Potentially at stake in this disagreement is the character of nuclear strategy in U.S. national security.3
The First Wave of Debates
In the early 1980s, at one of the lowest moments of U.S.-Soviet relations, several scientists began to model the atmospheric aftereffects of a general nuclear exchange between the two major nuclear powers. They found evidence that in the event of such a war, massive urban fires could loft into the atmosphere large plumes of soot and smoke that would disseminate into a hazy shroud spanning Earth. Climate models suggested that this massive influx of burned particulate matter into the atmosphere would absorb large amounts of solar energy, warming the upper atmosphere and keeping the soot and smoke aloft for years thereafter. This climatic perturbation would lead to dramatically darker and cooler conditions on Earth’s surface. Scientists foretold twilight conditions at noon and freezing temperatures in summer. They dubbed this phenomenon “nuclear winter.”4
Thereafter, U.S. and international agencies funded a series of large-scale studies on the nuclear winter hypothesis.5 Their findings attenuated the most extreme freezing predictions but ultimately reinforced the general understanding that a major nuclear exchange between the two superpowers would have catastrophic freezing effects on a planetary scale.
The nuclear winter theory, nevertheless, had its detractors. Its most critical opponents were military-affiliated scientists, particularly top scientists at Lawrence Livermore National Laboratory, who accused advocates of the nuclear winter hypothesis as playing politics and improperly evoking science to advance allegedly partisan goals.6 Ironically, many of these same scientists stood to benefit from increased public spending on nuclear weapons research and a hawkish approach to U.S.-Soviet relations. The strategic implications of nuclear winter could potentially upend the Reagan administration’s ongoing military buildup, which was particularly beneficial to the U.S. national nuclear laboratories.

A longstanding feud between astrophysicist Carl Sagan of Cornell University and nuclear physicist Edward Teller of Lawrence Livermore National Laboratory exemplified this split within the scientific community.7 Sagan, a member of the research group that first introduced the concept of nuclear winter, argued that the potential climatic consequences of a nuclear war would weaken the viability of a first-strike posture. Even if the United States prevailed in a nuclear war with little retaliatory damage to the U.S. homeland, the resultant climatic effects of many massive firestorms in Communist bloc cities would be so great as to threaten U.S. survivability, he reasoned. According to this logic, the United States would be reluctant to launch a nuclear strike at all, as a matter of self-preservation.
Teller, a fierce advocate of U.S. nuclear primacy, referred to Sagan as a “propagandizer” and suggested he was deploying environmental alarmism to advance his preferred political objectives. Teller did not directly contradict the findings of potential climatic cooling after nuclear war but instead argued that too many uncertainties existed to know definitively how nuclear war might alter the climate.
Ultimately, the end of the Cold War, the collapse of the Soviet Union, and the signing of nuclear arms reduction treaties significantly reduced the risk of a large-scale nuclear war. For nearly two decades, many scientists and policymakers shifted their attention from nuclear war’s climatic effects.
Nuclear-Climate Studies Revival
Beginning in 2007, atmospheric scientists at universities and civilian federal agencies began to take up the issue of nuclear war’s climatic impacts once again, citing nuclear proliferation and nuclear terrorism as potentially destabilizing threats to global security. Several independent scientists who had studied nuclear winter scenarios in the 1980s began to model the climatic effects of “smaller” nuclear wars between regional powers, such as India and Pakistan.8 Preliminary findings suggested that although the climatic effects of a less powerful nuclear exchange between such states would not constitute a nuclear winter per se, deleterious levels of global climate cooling could still occur.
At the same time, these scientists revisited the question of nuclear war between Russia and the United States, given the two nations’ substantially reduced stockpiles since the 1980s. They found that even with smaller nuclear arsenals, a U.S.-Russian war could “produce cooling as large or larger than that experienced 18,000 years ago during the coldest period of the last Ice Age.”9 This revived study into nuclear war’s climatic effects focused less on whether various nuclear scenarios met the amorphous threshold of “nuclear winter” and more on how nuclear wars of varying levels of severity might disrupt life-maintaining environmental, agricultural, and logistical systems around the world.
Over the next decade, the size of the scientific community interested in the subject steadily grew and improved insight into how regional and global nuclear wars might reconfigure Earth’s biogeochemical cycles. Some research focused on nuclear war’s disruption of the ozone layer, which would increase human exposure to carcinogenic ultraviolet radiation. Other work narrowed in on the implications for food production and distribution, with one study suggesting that an Indian-Pakistani nuclear war would reduce significantly rice cultivation in China for a decade thereafter. This revival of the subject, though, grew out of university and civilian federal agencies.10
Undergirding much of this research was the concept of self-assured destruction, harkening back to Sagan’s thinking on nuclear strategy in the 1980s.11 The concept posited that the collateral environmental impacts of even a nominally successful nuclear attack would have existential consequences upon the attacking state, thus weakening the credibility of a first-strike posture. Whereas the science of nuclear winter in the 1980s had initiated a protracted debate among scientists, policymakers, and the public, the slower and steadier development of the science during the Obama administration—a time of relative geopolitical stasis among the world’s major powers—did not draw as much attention from policy circles in Washington or the U.S. population generally.
A New High-Stakes Environment
The year 2017 marked a decided change in research into nuclear war’s environmental consequences. This was because of external political conditions that again made this research particularly relevant to international affairs, not because of the methods or findings of the research itself. Four major developments influenced this change: a series of international crises that increased the specter of nuclear war; the organization of many non-nuclear nations into a visible anti-nuclear coalition; the implementation of nuclear modernization efforts among nuclear-armed states; and the reemergence of scientists from NNSA laboratories into the literature on nuclear war’s climatic aftereffects.
Regarding the first development, the precipitous rise in the likelihood of nuclear warfare began during the U.S.-North Korean diplomatic crisis of 2017 but has since deepened to become a normative condition of modern geopolitics. Contributing factors to this new state of affairs include the erosion of relations between China and the United States, Russia’s invasion of Ukraine, Israel’s protracted military operations in the Gaza Strip, Iran, Lebanon, Qatar, Syria, and Yemen, and recurrent Indian-Pakistani border crises.12
Second, the passage of the Treaty on the Prohibition of Nuclear Weapons by the UN General Assembly in 2017 drew a stark contrast between nuclear states and non-nuclear states.13 The TPNW’s passing was the culmination of a process dating back to 2010, when many non-nuclear states began to take a more confrontational approach to nuclear disarmament, directly criticizing the logic of nuclear deterrence and focusing on “the unacceptable humanitarian consequences of nuclear violence” to delegitimize the nuclear status quo.14 This treaty cohered many non-nuclear states into an integrated and vocal bloc explicitly rejecting the logic of nuclear deterrence and calling for full denuclearization across all nuclear states. An important rationale for the treaty’s signatories was the prospect of severe climatic disruptions after nuclear war that could lead to catastrophic humanitarian harm globally.15
Third, nuclear modernization initiatives, which preceded 2017 but gained discernible momentum since then, have locked in the operational viability of existing nuclear arsenals for most of the 21st century. For example, although behind schedule, the new Sentinel intercontinental ballistic missile is expected to be operational until around 2075, extending the U.S. first-strike capability for generations. Essentially all nuclear states are now modernizing or expanding their nuclear stockpiles.16
Finally, scientists at NNSA laboratories resumed research into nuclear war’s environmental impacts.17 Much like their progenitors in the 1980s, they have called into question the severity of the climatic risks posed by nuclear war and emphasized the uncertainties within current modeling efforts.
Combined, these factors created a new terrain on which civilian scientists have had to contest the credibility of research on nuclear war’s environmental impacts. Their work has regained relevance with policymakers and strategists, yet they are facing additional scrutiny from scientific and political institutions that stand to benefit from an enhanced nuclear strike capability.
Adapting to a New Normal
Public confrontations on the environmental consequences of nuclear war have not been widespread since the 1980s. However, a new period of direct political action appears imminent. Scientists are organizing. For instance, the Physicists Coalition for Nuclear Threat Reduction is an emerging organization of practicing physicists that advocates for substantive changes to current nuclear stockpiles and policies with the eventual goal of nuclear disarmament.18 The coalition is actively recruiting within university physics departments across the country to grow its political strength.
Additionally, networks of scientists across national boundaries have become essential to research on nuclear war’s climatic aftereffects. Ag-GRID is an international crop modeling initiative that collaborates on modeling global agricultural productivity amid various climate change scenarios. One project within this initiative—the ANFOSa Project at the International Institute for Applied Systems Analysis in Austria—is specifically focusing on modeling food insecurity after nuclear war.19
Perhaps the most significant upcoming study is the United Nations Scientific Panel on the Effects of Nuclear War, expected to be published in 2027, which will examine the “physical effects and societal consequences of a nuclear war on a local, regional and planetary scale.”20 This will be the first time since 1988 that the UN has undertaken a study into nuclear war’s environmental aftereffects.21
a. Advanced ensemble projections for indirect impacts of nuclear conflict in global food systems
The Historical Role of Science in Society
Viewed historically, one can recognize how social and political contexts shape the present state of study into nuclear war’s climatic consequences. Scientists first broached the topic because nuclear war between the Soviet Union and the United States seemed plausible. They wanted to uncover the potential adverse outcomes of nuclear war and educate the public on the consequences of such a conflagration. Likewise, much of the scientific pushback against the nuclear winter hypothesis originated from institutions that would benefit materially from an aggressive nuclear posture. Neither of these approaches were politically neutral.

Even so, science is always a political process, in some form. To fully separate science from human subjectivity and social context is to not do science at all. One should not ask whether but how a particular scientific debate is political. Who gets to claim scientific authority? On what basis is this authority derived? Whom might a given research program help or harm? What public outcomes might result from the scientific research under consideration? Asking these questions can illuminate the power discrepancies and divergent institutional interests between civilian scientists and those at NNSA federal laboratories.
This is not to say that criticism of the findings of civilian scientists is always dubious—far from it. These scientists acknowledge the informed assumptions that go into their modeling work as well as the unknowns that require further investigation. As the National Academies report states, many uncertainties do, in fact, remain as to how nuclear war may reorder Earth’s environmental systems, and additional resources are needed to develop a greater level of confidence on the subject.
The Current State of Research and Future Prospects
What is at issue, instead, is the ways in which NNSA scientists interact with their civilian peers. NNSA scientists do not collaborate with those at universities or civilian research centers who have been working on this topic for years, even decades. Civilian scientists find out what NNSA laboratories are working on through conference presentations and publications. These laboratories have far greater resources at their disposal than university scientists. They could combine the experience of their civilian colleagues with their own institutional resources to develop experiments in which the informed assumptions, parameters, and methods in their modeling are more likely to be accepted communitywide. But they do not do this. Cultivating consensus does not seem to be their aim.
Instead, NNSA scientists describe their civilian colleagues as “the nuclear winter community” from which they are presumably separate.22 They imply political motivation on the part of civilian scientists and fail to acknowledge the structural interests of their own institutional affiliations. They claim the mantle of objectivity and question that of their civilian peers.
Take, for example, the perspective of one Los Alamos National Laboratory climate scientist, Manvendra Dubey, who presented before the National Academies consensus study committee in September 2023.23 One committee member asked Dubey about the sedimentation of urban fire particulate matter back to Earth’s surface. He elaborated a bit before shifting his focus to U.S. national security:
“There is another side [to] this problem, which is it has implications to national security … which is not my domain, but it’s out there. So, we need to be very objective. You know this issue of fear of not using [nuclear weapons] for whatever reason is, again, … skewed. [The United States] is very liberal and open-minded and science-driven, but, you know, other nations aren’t. So, I’m sure you’ve heard about the policy imperatives. So, we all don’t want impacts [from] nuclear weapons, but I think we [scientists] need to be very even handed when we talk about it.”
Dubey’s brief tangent reveals quite a bit about the logic at NNSA laboratories. His claim that the U.S. political class takes these issues seriously, whereas U.S. adversaries do not, is verifiably untrue. In the 1980s, Soviet Premier Mikhail Gorbachev took the prospect of nuclear winter far more seriously than did the Reagan administration. Recently, China was the only nuclear-armed nation to vote in favor of the UN study into the environmental effects of nuclear war. The United States abstained. Given that the Trump administration is currently burying congressionally mandated reports on climate change, Dubey’s understanding of the state of climate science in the United States and its adversaries was misguided.24
Additionally, Dubey’s conception of evenhandedness wrongfully conflates analytical disinterest with analytical conservatism. To claim that nuclear war potentially could have severe climatic cooling effects worldwide is not to lack impartiality. In fact, claiming that moderate estimates should be preferred over more severe estimates, regardless of what one finds from observation, is evidence of one’s own partiality.
When combined, these two assumptions—that the United States should not take seriously the concept of self-assured destruction because its adversaries will not, and that claims of less severe climatic effects should be favored over those of greater severity—align with the interests of those who favor a first-strike nuclear posture. The implementation of this military posture, which Los Alamos will materially benefit from, seems to be an abiding objective of NNSA scientists.
Ultimately, how societies choose to manage societal risks are political, rather than empirical, questions. Politicians and the public, rather than scientists, will decide how the potential environmental consequences of nuclear war shape nuclear policy. When scientists disagree on issues of such consequence, it is incumbent upon civil society to scrutinize the underlying institutional incentives that shape the debate. This scrutiny is crucial because the outcome of these debates may well shape whether a first-strike nuclear posture remains an abiding objective of U.S. nuclear strategy, or whether alternative forms of military and diplomatic engagement are more aligned with the interests of the nation—and the planet.
ENDNOTES
1. National Academies of Sciences, Engineering, and Medicine, Potential Environmental Effects of Nuclear War, The National Academies Press, Washington, DC, 2025.
2. National Academies of Sciences, Engineering, and Medicine, Risk Analysis Methods for Nuclear War and Nuclear Terrorism, The National Academies Press, Washington, DC, 2023; National Academies of Sciences, Engineering, and Medicine, Risk Analysis Methods for Nuclear War and Nuclear Terrorism: Phase II (Abbreviated Report of the CUI Version), The National Academies Press, Washington, DC, 2023; National Academies of Sciences, Engineering, and Medicine, Risk Analysis Methods for Nuclear War and Nuclear Terrorism (Expanded Abbreviated Report of the CUI Version), The National Academies Press, Washington, DC, 2024.
3. For brief historical and contemporary overviews of this debate, see Sean L. Malloy, “Weathering Nuclear War,” review of A Nuclear Winter’s Tale: Science and Politics in the 1980s, by Lawrence Badash, American Scientist, Vol. 98, No. 3 (May-June, 2010): pp. 242-245 and Alan Robock, Owen B. Toon, and Charles G. Bardeen, “Comment on ‘Climate impact of a regional nuclear weapon exchange: An improved assessment based on detailed source calculations’ by Reisner et al.” Journal of Geophysical Research: Atmospheres, Vol. 124 (2019): pp. 12,953-12,958.
4. Paul J. Crutzen and John W. Birks, “The Atmosphere After a Nuclear War: Twilight at Noon,” Ambio, Vol. 11, No. 2/3 (1982): pp. 114-125; R. P. Turco, O.B. Toon, T.P. Ackerman, J.B. Pollack, and Carl Sagan, “Nuclear Winter: Global Consequences of Multiple Nuclear Explosions,” Science, Vol. 222, No. 4630 (1983): 1,283-1,292.
5. William Burr, ed., “Investigating the Climate Impacts of Nuclear War,” National Security Archive, Briefing Book #872, October 30, 2024.
6. Paul Rubinson, “The global effects of nuclear winter: science and antinuclear protest in the United States and the Soviet Union during the 1980s,” Cold War History, Vol. 14, No. 1 (February 13, 2013): pp. 47-69.
7. Andrew J. Ross, “An Icy Feud in Planetary Science: Carl Sagan, Edward Teller, and the Ideological Roots of the Nuclear Winter Debates, 1980-1984,” Historical Studies in the Natural Sciences, Vol. 52, No. 2 (April 2022): pp. 90–222.
8. O.B. Toon, R.P. Turco, A. Robock, C. Bardeen, Luke Oman, and Georgiy L. Stenchikov, “Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism,” Atmospheric Chemistry and Physics, Vol. 7 (April 2007): pp. 1,973-2,002.
9. A. Robock, L. Oman, and G.L. Stenchikov, “Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences,” Journal of Geophysical Research, Vol. 112 (July 2007).
10. Michael J. Mills, O.B. Toon, Julia Lee-Taylor, and A. Robock, “Multidecadal global cooling and unprecedented ozone loss following a regional nuclear conflict,” Earth’s Future, Vol. 2 (2014), pp. 161-176 and Lili Xia and A. Robock, “Impacts of a nuclear war in South Asia on rice production in Mainland China,” Climate Change, Vol. 116 (May 2013), pp. 357-372.
11. A. Robock and O.B. Toon, “Self-assured destruction: The climate impacts of nuclear war,” Bulletin of the Atomic Scientists, September 1, 2012).
12. Ian Bremmer, “Welcome to a World Defined by Polarization, Instability, and Disruption,” Carnegie Reporter Vol. 16, No. 1 (Summer 2025), February 24, 2025.
13. Beatrix Immenkamp, “Treaty on the prohibition of nuclear weapons — The ‘Ban Treaty’” European Parliamentary Research Service, January 2021.
14. Rebecca Davis Gibbons, review of Banning the Bomb: Smashing the Patriarchy by Ray Acheson and The Treaty Prohibiting Nuclear Weapons: How It Was Achieved and Why It Matters by Alexander Kmentt, Arms Control Today, November 2021.
15. “Second Meeting of States Parties to the Treaty on the Prohibition of Nuclear Weapons,” UN Office for Disarmament Affairs, October 27, 2023.
16. Xiaodon Liang, “U.S. Nuclear Modernization Programs,” Arms Control Association, and “Nuclear risks grow as new arms race looms—new SIPRI Yearbook out now,” Stockholm International Peace Research Institute June 16, 2025.
17. Jon Reisner, Gennaro D’Angelo, Eunmo Koo, Wesley Even, Matthew Hecht, Elizabeth Hunke, Darin Comeau, Randall Bos, and James Cooley, “Climate Impact of a Regional Nuclear Weapons Exchange: An Improved Assessment Based On Detailed Source Calculations,” Journal of Geophysical Research: Atmospheres, Vol. 123, No. 5 (2018), pp. 2,752-2,772.
18. Stewart Prager and Frank von Hippel “Physicists need to be talking about nuclear weapons,” Physics Today, Vol. 76, No. 8 (2023): pp. 10-11.
19. Pavel Kiparisov, “The looming shadow of nuclear winter,” ANFOS Project at the International Institute for Applied Systems Analysis, May 16, 2025.
20. UN General Assembly resolution adopted on December 24, 2024, “Nuclear war effects and scientific research,” United Nations, December 31, 2024.
21. François Diaz-Maurin, “UN to conduct new study of the broad impacts of nuclear war. Not all countries want to know,” Bulletin of the Atomic Scientists, November 5, 2024 and Daisy Dobrijevic “As NASA’s budget shrinks, Europe doubles down on Earth science: ‘Climate change is the defining challenge of our generation,’” Space.com, July 11, 2025.
22. Jon Reisner, “Megafires: A New Fire Paradigm” Los Alamos National Laboratory, November 15, 2021.
23. “Independent Study on Potential Environmental Effects of Nuclear War | Meeting #4,” National Academies of Sciences, Engineering, & Medicine, September 19, 2023.
24. Seth Borenstein, “The Trump administration reverses its promise to publish key climate reports online,” Associated Press, July 14, 2025.
Andrew J. Ross is a doctoral candidate in history at Georgetown University and a Guggenheim Fellow at the National Air and Space Museum.
A series of wargames conducted by the Center for Strategic and International Studies and the Massachusetts Institute of Technology went against the recommendations of war hawks who favor a nuclear weapons buildup.
October 2025
By Matthew Cancian
In recent years, the United States has embarked on a modernization of its nuclear weapons arsenal that is projected to cost upward of $540 billion for acquisition alone.1 Nevertheless, there is a growing chorus of experts, defense contractors, and politicians who want to go bigger. Recent analyses by such groups as the Heritage Foundation, the Atlantic Council, and the 2023 Congressional Commission on the Strategic Posture of the United States make the case for an increase in the quantity and variety of U.S. nuclear weapons.2 Their vision goes beyond the long-delayed nuclear modernization program that is already underway; these nuclear hawks want the U.S. president to have even more warheads and more tactical nuclear options to use in any prospective great-power war.3

Despite such arguments, President Joe Biden and now President Donald Trump seem to believe the current nuclear arsenal is sufficient. Their judgments are supported by 15 iterations of a U.S.-China wargame set in 2028, which found that U.S. nuclear superiority did not factor into the deterrence calculations of Chinese teams and that the United States did not benefit from launching damage-limiting first strikes with its superior arsenal.4 Expanding the arsenal would divert funding from strengthening U.S. conventional deterrence, would make U.S. nuclear use more likely, and threaten to start an unlimited arms race instead of moving toward arms control.
Presidential Skepticism
Successive U.S. presidents have been skeptical about nuclear expansion. President Joe Biden argued that “a nuclear war cannot be won and must never be fought.”5 His national security advisor, Jake Sullivan, more explicitly tied this view to quantitative limitations: “I want to be clear here: The United States does not need to increase our nuclear forces to outnumber the combined total of our competitors in order to successfully deter them.”6 Despite having radically different policies from Biden on so many issues, President Donald Trump expressed a similar idea: “There’s no reason for us to be building brand-new nuclear weapons; we already have so many.”7 So, who’s right? The nuclear hawks or the presidents?
A series of wargames conducted by the Center for Strategic and International Studies and the Massachusetts Institute of Technology supported the presidents against the recommendations of the nuclear hawks. To examine the causes and consequences of deterrence failures, our team modified a previous U.S.-China wargame to include nuclear weapons and ran it 15 times.8 Each iteration had different members of the U.S. national security community as participants, with members of the intelligence community playing China. Despite the varied composition of teams, U.S. nuclear superiority and counterforce capabilities had no impact on the decisions of the China teams’ decision-making.
Among the seven China teams that recommended and used nuclear weapons, all recognized the extreme risk of such a choice, knowing that the United States could inflict catastrophic damage.9 However, the scale of potential devastation—whether from 300 or 1,000 U.S. warheads—did not alter the teams’ willingness to proceed. Furthermore, no U.S. team believed that it lacked tactical nuclear options sufficient to retaliate against Chinese nuclear attacks, if it so chose. Therefore, the study found no evidence that expanding the U.S. nuclear arsenal quantitatively or qualitatively would have enhanced deterrence.
The wargaming exercise strongly suggests that the United States should embrace the continuity between Biden and Trump by resisting the urge to expand the size and diversity of its nuclear arsenal. To dissuade China from gambling for resurrection—by using nuclear weapons to salvage a failing conventional campaign—during a future war, U.S. diplomacy will be more important than nuclear threats.10 Expanding the U.S. nuclear arsenal is not only wasteful because it would divert U.S. funding from strengthening its conventional deterrence; it is also dangerous because it makes U.S. first use of nuclear weapons more likely and shifts diplomacy toward an unconstrained arms race.11 The United States must be prepared to successfully prosecute a high-end conventional war while at the same time providing face-saving offramps to the adversary to avert a nuclear conflict that would be damaging to all sides. Following presidential wisdom not expanding the nuclear weapons is the way to do this.
Nuclear Superiority vs. Nuclear Sufficiency
Separate from the kinds of nuclear weapons that are built is the question of quantity: Does nuclear superiority provide more deterrence, or is sufficiency all that matters?
The return of great-power competition, with the potential for great-power war, has raised the specter of the United States having to deter two nuclear adversaries, China and Russia. Russia seemed on the verge of using nuclear weapons in the October 2022 crisis, when it suffered dramatic battlefield defeats in Ukraine.12 Such worries have continued, for example in light of President Vladimir Putin codifying changes to Russia’s nuclear doctrine in November 2024 to broaden the range of nuclear employment scenarios.13 Meanwhile, China has been expanding its nuclear arsenal against a backdrop of increasing concerns about a possible invasion of Taiwan.14 This has led some analysts to conclude that if nuclear weapons are becoming more salient and U.S. adversaries are acquiring more of them, then surely the United States also needs to expand its force size to maintain deterrence.15
The argument that U.S. nuclear superiority leads to improved deterrence is superficially intuitive and has some scholarly support. One proponent of this concept argues that a larger nuclear arsenal means that, in retaliation to an adversary’s first strike, more U.S. weapons would penetrate an adversary’s defenses, more cities would be struck, and more people would be killed in a countervalue attack.16 A larger number of nuclear weapons would also be helpful in a disarming nuclear first strike on an adversary.17
According to the authors of the 2023 Commission on the Strategic Posture of the United States, expansion of the U.S. arsenal is needed to, “Address the larger number of targets due to the growing Chinese nuclear threat.”18 Thus, an expanded arsenal theoretically offers benefits both under a counterforce (targeting an enemy’s nuclear weapons) or countervalue (targeting an enemy’s civilian population) nuclear strategy. Meanwhile, Vipin Narang and Pranay Vaddi raise the specter of coordinated action by the Russians, Chinese, and/or North Koreans to justify their advocacy of “more, different, and better nuclear capabilities.”19

However, there are also theoretical reasons why nuclear sufficiency, not relative capabilities, matter for deterrence. Although the early days of the Cold War were characterized by a headlong rush toward more capability, U.S. President Dwight Eisenhower’s Air Force secretary saw past this to an age when any nuclear war would be “an unthinkable catastrophe for both sides.”20 In theoretical terms, as long as a country possesses a secure second strike, the magnitude of that second strike is not consequential for deterrence. In a counter to proponents of nuclear expansion, other contemporary scholars have proposed that the United States should embrace nuclear sufficiency despite Russia’s saber-rattling and China’s buildup.21
A first step in adjudicating nuclear superiority and sufficiency is to imagine how these concepts would play out in a real-world situation. Imagine two different worlds with illustrative numbers in which there is a 2027 war between China and the United States. In the first world, the United States has maintained current nuclear force levels. Following a countervalue logic, this “limited” force could deliver one nuclear weapon to each of the 100 largest Chinese cities while maintaining a similar reserve capability against Russia. Alternatively, following a counterforce logic, the United States could strike first to limit damage from China, such that the 100 largest U.S. cities would be struck by Chinese retaliation. In the alternate world, the United States has a larger arsenal: Now it can strike the 200 largest Chinese cities while maintaining a reserve capability, or it could launch a nuclear first strike against China so that only the 50 largest U.S. cities would be struck in a Chinese nuclear retaliation.
Would China be more deterred from nuclear escalation in the counterfactual world where the United States has a larger arsenal than in the world where the United States maintains its current arsenal size? There are certainly measurable differences—in the millions of deaths on both sides—between the two worlds. However, just because something is measurable does not mean that it is significant. It is possible that quantitative differences in nuclear arsenals could have no influence on nuclear deterrence, as long as both sides have sufficient arsenals. Historic cases give some insight, but differences in coding can lead to differences in findings. Another methodological possibility is wargaming.22
Wargames Support a Strategy of Nuclear Sufficiency
To explore the drivers and consequences of deterrence failures during the U.S. military’s pacing scenario—a war against China during a Taiwan invasion in 2028—my co-authors and I modified added nuclear posturing and use to our existing wargame and ran it 15 times.23 Previous wargames have mostly either ended at nuclear use or investigated the results of scripted nuclear use, rather than allowing players to choose nuclear use and then navigate its consequences.24 Chapter 4 of the report contains a more complete description of methodology. It is important to note here that the project focused on understanding the military logic of using nuclear weapons in a Taiwan scenario and did not address the likelihood of their actual use. Political factors were minimized by defining players as operational commanders, but some players still considered political aspects, such as the international reputational costs of breaking the nuclear taboo. The frequency of nuclear-weapon use in the game iterations did not reflect their probability in real conflict, as political leaders might use nuclear weapons differently or act as a brake against their use due to fears of escalation and moral opprobrium.
These 15 games produced the full gamut of nuclear scenarios, underlining the inherent unpredictability of nuclear escalation. Some China teams opened the games with a High-altitude Electro-Magnetic Pulse (HEMP) nuclear weapon. Other times no team used any nuclear weapons, successfully concluding with a ceasefire. However, many games saw nuclear use beyond HEMP. Although this sometimes led to ceasefires, in other scenarios it also led to escalatory spirals that ended in a global conflagration.

The clearest risk of nuclear first use came from a China team that believed that its invasion was failing and wanted to gamble for resurrection. Before reaching this critical decision, China teams experienced great initial successes in establishing a beachhead on Taiwan but faced increasing setbacks. Over time, the Chinese amphibious fleet suffered heavy losses, and logistical support dwindled, causing a decline in Chinese combat power on the island. By weeks three to five, with supplies inadequate and no functioning captured port or airfield, defeat loomed, forcing the China teams to choose between an adverse settlement, likely defeat, or the use of nuclear weapons.
U.S. quantitative nuclear superiority was understood by the China teams, but it did not deter them. All teams recognized that the United States maintained an advantage in the nuclear domain despite the significant growth of the nuclear inventories of China’s People’s Liberation Army in the decade leading up to 2028.25 As occurred in other wargames, the China teams were aware that using nuclear weapons could provoke U.S. retaliation. They noted that the United States had more escalatory options and the capability to launch a damage-limiting counterforce strike against China.26 However, they believed that as long as the United States could not execute a disarming counterforce strike, strategic nuclear attacks were unlikely. Thus, U.S. nuclear superiority was not a primary factor in the Chinese calculations, and the China teams that chose not to use nuclear weapons were influenced by factors other than their nuclear inferiority.
Similarly, the China teams did not consider the magnitude of U.S. countervalue retaliation as an important factor in deterrence. This is in line with Robert Jervis’s theory of the nuclear revolution. According to Jervis, the possession of a few nuclear weapons by a state is sufficient to deter an adversary, regardless of whether the adversary possesses a larger arsenal.27 The logic behind this is that the destructive power of nuclear weapons is so immense that even a small number can inflict unacceptable damage, rendering the exact number of weapons less significant. Therefore, states are not deterred by the adversary’s larger nuclear arsenal because the mutual threat of destruction, inherent in even a limited number of nuclear weapons, ensures deterrence.
Nor did U.S. teams realize any benefits from launching damage-limiting nuclear first strikes against China’s nuclear forces. In the two games where Chinese nuclear forces were subjected to large damage-limiting nuclear attacks, the China teams maintained enough nuclear capability to launch counterattacks on the U.S. homeland. They withstood the U.S. counterforce attack and used their remaining mobile intercontinental ballistic missiles (ICBM) to achieve a favorable outcome in both games (after destroying several U.S. cities in a process of Schellingesque nuclear bargaining).28 Consequently, counterforce attacks on China did not provide U.S. teams with decisive war-winning advantages.
Even a U.S. nuclear buildup would be unable to achieve the first-strike capability that proponents envision, absent an exquisite penetration of Chinese command and control networks. China’s development and deployment of mobile ICBMs are critical in granting the country a credible second-strike capability. These missiles are mounted on mobile launch platforms, allowing them to be transported and hidden across various terrains, making it difficult for adversaries to track and target them. The mobility of these ICBMs enhances China’s second-strike capability, ensuring that it can retaliate even if its fixed nuclear sites are compromised in a first strike. Additionally, China’s development of advanced missile technologies, including multiple independently targetable reentry vehicles, further bolsters the effectiveness and survivability of its mobile ICBM force. Furthermore, China could simply build more of these systems as they see the United States building up its own nuclear forces in a quixotic pursuit of a disarming first strike. All of this ignores the moral questions, global outcry, and severe political repercussions that would be entailed by a nuclear first strike.
The Illogic of Nuclear Warfighting
In addition to advocating for more nuclear weapons writ large, many nuclear hawks also want increased diversity of U.S. tactical nuclear weapons. Much of the debate has focused on the nuclear-capable, sea-launched cruise missile, which was forced on the Biden administration by Congress.29 But the call is broader, with a recent article advocating for the United States to acquire more “non-strategic nuclear weapons” to match Russian and Chinese capabilities.30 This would entail procuring not only medium range ballistic missiles such as the Russian Iskander-M or the Chinese DF-21, but also the Russian Kalibr-class cruise missiles and even the Poseidon underwater drone.31
It is unclear, however, how more diverse weapons would help the United States in either deterring or fighting a nuclear war. Matching the nuclear delivery means of all potential adversaries would be difficult and would not guarantee symmetric effects. For instance, although a U.S. Iskander-class weapon based in NATO countries could reach key cities in Russia, Russian Iskanders cannot reach U.S. territory (exactly as was the case in the Cold War). Symmetry of technology and delivery profile does not equate to symmetry of effects.
In the series of wargames featuring scenarios on nuclear escalation in Taiwan, there was no point when participants believed that a Chinese nuclear attack with medium-range ballistic missiles would not elicit a U.S. response because the United States could only respond with air-launched cruise missiles, gravity bombs, and silo-launched or submarine-launched ICBMs. Even if a Russian or Chinese leader believed that a nuclear first strike would not elicit a U.S. response because the United States lacked a missile with a corresponding flight pattern, that would be a slender reed on which to embark on a potentially cataclysmic action.
Moreover, if nuclear warfighting with China or Russia is envisaged, there is no clear ceiling on how many nuclear weapons would be needed. A point often made by nuclear hawks is that nuclear weapons individually are not as destructive as commonly portrayed.32 This is certainly true. However, it would be almost impossible to gain the “ability to destroy sufficient levels of opponents’ fielded military forces and associated support infrastructure such that they are unable to operate effectively on the field of battle, therefore leaving one free to impose one’s political will upon opponents or force them to accept a cessation of hostilities,” as assessed by one nuclear weapons advocacy paper.33 This approach would envision the ability to launch thousands of nuclear attacks on Chinese or Russian ground forces, dispersed as they are in large territories.
In the wargames, the only time that the United States was able to successfully retaliate against China’s nuclear first use was with limited employment against a small target set. (Eight warheads were required to completely neutralize the Chinese ground forces on Taiwan during that game according to the models that we constructed using data provided by our sponsor.) In this iteration, China launched a nuclear attack against Taiwanese ground forces. With the nuclear forces in the current U.S. program of record, the United States had several options for delivering a limited counterblow against the Chinese ground forces on Taiwan. This led to both sides accepting a status quo ante peace, albeit in a world that would be changed profoundly in ways that cannot be modeled, and that would certainly be worse than if both parties had reached a negotiated settlement before nuclear use.
Finally, a focus on nuclear warfighting detracts from the primary utility of nuclear weapons: bargaining. In the wargames, the most successful outcomes came from diplomacy backed by nuclear force, not from battlefield employment. Perhaps looking at the results of exercises such as Carte Blanche, Schelling concluded that, “The adequacy of our nuclear weapons in Europe is not determined by whether we could win a full-scale European nuclear campaign…. Their function is to make the triggering of inadvertent or pre-emptive war a frighteningly probable consequence of their large-scale use or of a massive nuclear effort to destroy them.”34
The ability of the wargames to escalate to nuclear use—all the way up to a global nuclear conflagration—surprised not only players, but also the study’s authors. Juxtaposing that with the nuclear hawks’ desire to “impose one’s political will” makes the disconnect between political theory and the advocacy for battlefield nuclear weapons clear.
However, if the maxim, ceteris paribus—more options are better than fewer—is true, why not acquire more nuclear weapons and more varying types? These wargames do not cover all conceivable scenarios. Many players on the U.S. team pointed to concerns about Russia when weighing their nuclear responses to China. If more nuclear options do not help in the U.S. pacing scenario, why not acquire them on the chance that they are useful in other scenarios?
Wasteful and Dangerous
There are three ways in which acquiring additional nuclear weapons would be actively harmful: by diverting money from conventional arms, by increasing the temptation for U.S. nuclear first use, and by damaging the prospects for arms control discussions.
It is crucial to invest in conventional weapons such as bombers, submarines, and long-range anti-ship missiles to deter China from starting a conflict in the first place. U.S. Secretary of Defense Pete Hegseth emphasized the importance of funding conventional warfighting capabilities as one of his priorities.35 The Strategic Posture Review explicitly states that it did not conduct a cost analysis when recommending nuclear expansion, but any meaningful expansion would severely impact conventional warfighting. The wargames demonstrate the danger of China miscalculating its ability to conquer Taiwan rapidly, as Putin did in Ukraine.36 Increasing U.S. conventional capabilities rather than nuclear arms would make such a miscalculation less likely.
The growing discussions of U.S. nuclear first use in a Taiwan scenario also highlight the danger that increasing the U.S. arsenal would make U.S. nuclear first use more likely. There is a large literature on how bureaucracies shape the decisions of U.S. presidents in crisis, from the Cuban missile crisis to President Barack Obama’s Afghanistan surge.37 Having built a nuclear “hammer,” the national security bureaucracy would feel the need to justify that expenditure by finding a “nail.” There is a risk that, during a war with China, some element of the bureaucracy would be able to convince a U.S. president that nuclear first use would lead to a successful outcome. Although U.S. first use never paid off in the wargames, it is possible that it might; however, the U.S. president should not make decisions based on wishful thinking.
Finally, U.S. nuclear expansion would jeopardize future arms control discussions with China. China’s nuclear strategy is highly sensitive to U.S. capabilities; any significant enhancement of the U.S. nuclear arsenal may prompt China to expand its own nuclear forces to ensure a credible deterrent.38 This dynamic can escalate tensions and make arms control negotiations more challenging.39 Furthermore, acknowledging the mutual vulnerability of China and the United States to nuclear attack is a key to any nuclear negotiations with China.40
A U.S. nuclear buildup could diminish trust and reduce the incentives for both sides to engage in arms control agreements. Admittedly, China’s interest in negotiations has been tepid, as was its response to Trump’s desire to reduce the global nuclear arsenal.41 However, there are areas on which progress could be made.42 Furthermore, given the consequences of failure, any negotiating effort is worth making, especially when that effort simply entails not wasting tens or hundreds of billions of dollars on unnecessary nuclear weapons.
ENDNOTES
1. Xiaodon Liang, “U.S. Nuclear Modernization Programs,” Arms Control Association, August 2024.
2. For examples, see: Greg Weaver and Amy Woolf, “Requirements for Nuclear Deterrence and Arms Control in a Two-Peer Nuclear Peer Environment,” Atlantic Council, February 2, 2024; Robert Peters, “Nuclear Posture Review: The Next Administration Building the Nuclear Arsenal for the 21st Century,” The Heritage Foundation, July 30, 2024; and Congressional Commission on the Strategic Posture of the United States, “America’s Strategic Posture: The Final Report of the Congressional Commission on the Strategic Posture of the United States,” U.S. Congress, October 2023.
3. For an early warning about the delayed nuclear modernization, see Mackenzie Eaglen and Kingston Reif, “The Ticking Nuclear Budget Time Bomb,” War on the Rocks, October 25, 2018.
4. For the report, see: Mark Cancian, Matthew Cancian, and Eric Heginbotham, “Confronting Armageddon: Wargaming Nuclear Deterrence and Its Failures in a U.S.–China Conflict over Taiwan,” Center for Strategic and International Studies, December 13, 2024.
5. President Joe Biden, “Joint Statement of the Leaders of the Five Nuclear-Weapon States on Preventing Nuclear War and Avoiding Arms Races,” The White House, January 3, 2022.
6. “Remarks by National Security Advisor Jake Sullivan,” presented at the Arms Control Association Annual Forum, The White House, June 2, 2023.
7. President Donald Trump’s remarks to press on February 13, 2025, published on YouTube by ABC News, “Trump: There’s no reason for us to be building brand new nuclear weapons,” February 13, 2025.
8. For the original project on conventional invasion, see Mark F. Cancian, Matthew Cancian, and Eric Heginbotham, “The First Battle of the Next War: Wargaming a Chinese Invasion of Taiwan,” Center for Strategic and International Studies, January 9, 2023.
9. It should be noted that the Chinese themselves are less inclined to countenance nuclear use in a war with the United States over Taiwan. See Fiona S. Cunningham and M. Taylor Fravel, “Dangerous Confidence? Chinese Views on Nuclear Escalation,” International Security Vol. 44, No. 2 (October 1, 2019): pp. 61-109. This point was reiterated by Tong Zhao during the CSIS rollout event for the wargames report. Matthew Cancian, moderator, “Confronting Armageddon: Wargaming Nuclear Deterrence and Its Failures in a U.S.-China Conflict over Taiwan,” panel discussion with Kari Bingen, Charles Glaser, and Tong Zhao, Center for Strategic and International Studies, December 13, 2024.
10. The role of diplomacy and politics in discussions of military scenarios is often overlooked. For a treatment of other political factors in the Taiwan scenario, see: Matthew F. Cancian, “States of Denial: Sensibly Defending Taiwan,” in Survival: April-May 2025, edited by the International Institute for Strategic Studies, Routledge, 2025, p. 25.
11. Daryl G. Kimball, “Why We Must Reject Calls for a U.S. Nuclear Buildup.” Arms Control Today Vol. 53, No. 9 (November 2023): p. 3.
12. Lachlan Mackenzie, “Six Days in October: Russia’s Dirty Bomb Signaling and the Return of Nuclear Crises,” Center for Strategic and International Studies. September 4, 2024.
13. For a fuller discussion of Russian nuclear signaling, see: Anya L. Fink, “Russia’s Nuclear and Coercive Signaling During the War in Ukraine.” Congressional Research Service, November 26, 2024.
14. The most recent China Military Power Report covers this nuclear expansion in greater detail than previous reports. See: U.S. Department of Defense, “Military and Security Developments Involving the People’s Republic of China 2024,” December 18, 2024.
15. Most explicitly, see Matthew Kroenig, “Washington Must Prepare for War With Both Russia and China.” Foreign Policy, November 15, 2024.
16. Matthew Kroenig, The Logic of American Nuclear Strategy: Why Strategic Superiority Matters, New York: Oxford University Press, 2020.
17. Although nuclear expansion advocates never say that the aim of nuclear expansion is to improve the U.S. capability to launch a damage-limiting first strike, a damage-limiting second strike is paradoxical and the United States does not have a countervalue nuclear doctrine. Thus, advocates of nuclear expansion use phrases like “hold at risk” adversary nuclear forces. For example, see: Patty-Jane Geller, “China’s Nuclear Expansion and Its Implications for U.S. Strategy and Security,” The Heritage Foundation, September 14, 2022.
18. Congressional Commission on the Strategic Posture of the United States, 2023.
19. Vipin Narang and Pranay Vaddi, “How to Survive the New Nuclear Age,” Foreign Affairs, June 24, 2025.
20. I.F. Stone, “Nixon and the Arms Race: How Much Is Sufficiency?” The New York Review of Books, March 27, 1969.
21. Charles L. Glaser, James M. Acton, and Steve Fetter, “The U.S. Nuclear Arsenal Can Deter Both China and Russia,” Foreign Affairs, October 5, 2023.
22. Introduction by James Goldgeier in Mathew Fuhrmann and Diane Labrosse, eds., “Roundtable 10-25 on The Logic of American Nuclear Strategy: Why Strategic Superiority Matters,” Robert Jervis International Security Studies Forum, H-Diplo | ISSF Roundtable, Volume X, No. 25 (2019).
24. See, Stacie Pettyjohn, Becca Wasser, and Chris Dougherty, Dangerous Straits: Wargaming a Future Conflict with Taiwan (Washington, DC: CNAS, 2022); Stacie Pettyjohn and Hannah Dennis, Avoiding the Brink: Escalation Management in a War to Defend Taiwan (Washington, DC: CNAS, February 2023), ; David Shullman, John Culver, Kitsch Liao, and Samantha Wong, Adapting US Strategy to Account for China’s Transformation into a Peer Nuclear Power. Atlantic Council, 2024; Andrew Metrick, Philip Sheers, and Stacie Pettyjohn. Over the Brink: Escalation Management in a Protracted War, Center for New American Security, 2024.
25. A fact acknowledged even by nuclear hawks. See “China’s Emergence as a Second Nuclear Peer: Implications for U.S. Nuclear Deterrence Strategy,” Study group convened by the Center for Global Security Research at Lawrence Livermore National Laboratory, March 14, 2023; Greg Weaver and Amy Woolf, “Requirements for Nuclear Deterrence and Arms Control in a Two-Peer Nuclear Peer Environment,” Atlantic Council, February 2, 2024.
26. Andrew Metrick, Philip Sheers, and Stacie Pettyjohn, “Over the Brink: Escalation Management in a Protracted War,” Center for a New American Security, August 6, 2024.
27. Although the term was not coined by Jervis, his remains the canonical text on its interpretation. See Robert Jervis, The Meaning of the Nuclear Revolution: Statecraft and the Prospect of Armageddon, Cornell University Press, 1989.
28. “Paper Prepared by Thomas C. Schelling,” in Foreign Relations of the United States, 1961-1963, Volume XIV, Berlin Crisis, 1961-1962, Document 56, U.S. Department of State, Office of the Historian, July 5, 1961.
29. Xiaodon Liang, “U.S. Starts Work on Nuclear-Capable Missile,” Arms Control Today, July/August 2024.
30. Charles Richard, Franklin Miller, and Robert Peters, “Nuclear Deterrence vs. Nuclear Warfighting: Is There a Difference and Does It Matter?” The National Institute for Public Policy, No. 623, April 15, 2025.
31. Hans M. Kristensen, Matt Korda, Eliana Johns, and Mackenzie Knight-Boyle, “Russian nuclear weapons, 2024,” Bulletin of the Atomic Scientists, Vol. 80, No. 2 (March 7, 2024): pp. 118-45.
32. Tim Goorley, “Nuclear Weapons Options and Effects,” Presented at the Materials Science in Extreme Environments, John Hopkins University, March 12, 2024.
33. Richard, Miller, and Peters, 2025.
34. Carte Blanche saw 355 simulated atomic bomb uses in a NATO-Soviet war. See Der Spiegel, “Überholt wie Pfeil und Bogen,” July 12, 1955. For the Schelling quotation, see Schelling, 1961.
35. David Vergun, “Pentagon Prioritizes Homeland Defense, Warfighting, Slashing Wasteful Spending” DOD News, U.S. Department of Defense, February 9, 2025.
36. Mark F. Cancian, “Putin’s Invasion Was Immoral, Not Irrational,” Center for Strategic and International Studies, May 10, 2022.
37. For an early discussion of the role of bureaucratic politics in the Cuban Missile Crisis, see Graham T. Allison, “Conceptual Models and the Cuban Missile Crisis,” The American Political Science Review, Vol. 63, No. 3 (September 1969): pp. 689-718. On the surge, see Kevin Marsh, “Obama’s Surge: A Bureaucratic Politics Analysis of the Decision to Order a Troop Surge in the Afghanistan War,” Foreign Policy Analysis, Vol. 10, No. 3 (2014): pp. 265-288.
38. As has occurred in the past. See Joanne Tompkins, “How U.S. Strategic Policy Is Changing China’s Nuclear Plans.” Arms Control Today, January 2003.
39. Tong Zhao, “Dangerous Parallax: Chinese-U.S. Nuclear Risks in Trump’s Second Term,” Arms Control Today, December 2024.
40. David Santoro, ed., “US-China Mutual Vulnerability Perspectives on the Debate,” Pacific Forum, Issues & Insights, Vol. 22, SR2, May 2022.
41. “Foreign Ministry Spokesperson Guo Jiakun’s Regular Press Conference on February 14, 2025,” Ministry of Foreign Affairs of the People’s Republic of China.
42. Tong Zhao, “Underlying Challenges and Near-Term Opportunities for Engaging China,” Arms Control Today, January/February 2024.
Although officials say diplomacy is still possible, the re-imposition of sanctions effectively ends the 2015 nuclear deal that U.S. President Donald Trump unilaterally abandoned in 2018.
October 2025
By Kelsey Davenport
Iran said it would suspend cooperation with the International Atomic Energy Agency (IAEA) after the UN Security Council reimposed sanctions and restrictions on Tehran’s nuclear and missile programs. But details were unclear.

Iranian President Masoud Pezeshkian told reporters Sept. 26 that the reimposition of sanctions was “unfair, unjust, and illegal.” After the measures were reimposed, he said in a Sept. 29 speech that Iran will not “bow down” to sanctions pressure.
The Security Council decision came a decade after a landmark international agreement called the Joint Comprehensive Plan of Action (JCPOA) imposed tight controls on Iran’s nuclear programs in return for a lifting of sanctions. In 2018, U.S. President Donald Trump unilaterally abandoned the agreement. Iran initially complied with its commitments but eventually resumed prohibited activities. In addition to the United States, other parties to the deal were China, Russia, France, Germany and the United Kingdom.
During the Sept. 26 press conference, Pezeshkian said that Iran will not leave the nuclear Nonproliferation Treaty (NPT) in response to the reimposition. But Iran said it would suspend a Sept. 9 arrangement that Foreign Minister Abbas Araghchi reached with the IAEA to restart cooperation, after Iran suspended safeguards following the Israeli and U.S. strikes on its nuclear facilities in June. Iran is legally required to implement a safeguards agreement as an NPT member.
The reimposition of UN Security Council resolutions on Iran from 2006 to 2010 took effect Sept. 28 as expected, 30 days after a request from France, Germany, and the United Kingdom—known as the E3—to restore the measures. They cited Iran’s violations of the 2015 nuclear deal as the reason for reimposition. (See ACT, September 2025.)
U.S. Secretary of State Marco Rubio said in a Sept. 27 statement that the reimposition of sanctions sends “a clear message” that Iran will be “held to account.” He said that “diplomacy is still an option” but “Iran must accept direct talks.”
In addition to sanctions, the Security Council resolutions restore prohibitions on Iranian nuclear activities—including uranium enrichment and missile development—that were lifted by Security Council Resolution 2231, which endorsed the JCPOA.
The three European countries were able to reimpose the previous resolutions using a unique mechanism contained in Resolution 2231, known as “snapback,” that cannot be blocked.
In a Sept. 19 Security Council vote to extend the JCPOA, only Algeria, China, Pakistan, and Russia voted in favor of the measure. The Security Council needed to pass that resolution to prevent the reimposition of the previous resolutions.
The E3 said in a Sept. 28 statement that they “made every effort” to avoid snapback and that “Iran did not engage seriously” with their offer to extend snapback in exchange for Iran’s commitment to resume talks with the United States, meet its IAEA safeguards obligations, and address its highly enriched uranium stockpiles. The E3 urged all states to implement the reimposed sanctions.
In a Sept. 26 press briefing, Araghchi said Iran showed “good faith by presenting good and doable proposals which could have resolved this problem,” but Iran’s “diplomacy has been blocked.” He suggested that Iran and France made progress on a framework that could have extended snapback, but France was “unable to secure the approval of the United States.”
Araghchi did not present specifics on Iran’s proposal, but he referenced an agreement he signed with IAEA Director-General Rafael Mariano Grossi in Cairo Sept. 9 as a sign of Tehran’s willingness to engage. The text of the Cairo agreement was not made public, and Araghchi and Grossi offered slightly different descriptions of what it contained.
Araghchi told Iranian state TV Sept. 10 that “the nature of [IAEA] access will have to be discussed at an appropriate time” and will be “based on reports that Iran will issue.”
Grossi said the Cairo agreement provided a “clear understanding of the procedures for inspections.” He said it was “fully in line with the relevant provisions” of Iran’s comprehensive safeguards agreement.
The Europeans suggested the agreement was insufficient because it did not include specific timelines for accessing nuclear sites in Iran that were attacked by Israel and the United States. The IAEA has had access to Iran’s Bushehr nuclear power reactor and the Tehran Research Reactor, neither of which were targeted by U.S. and Israeli strikes.
The Europeans also sought information on the status of Iran’s stockpile of uranium-235 enriched to 60 percent. According to a Sept. 3 IAEA report, Iran had 441 kilograms of uranium enriched to that level before the June 13 strikes. Iran likely moved the material to the underground facility at Esfahan that was too deeply buried to be destroyed by U.S. strikes. The entrance to that facility was struck, however, rendering the material inaccessible. (See ACT, July/August 2025.)
Araghchi told the state-run IRIB News Agency in a Sept. 11 interview that the Atomic Energy Organization of Iran is evaluating “whether these materials are accessible or not, and the status of some of them.”
Pezeshkian said Iran was willing to talk to the E3 and the United States at the United Nations, but U.S. officials did not show up for the meeting. He suggested that Iran had reached “understandings” with the Europeans, but the United States rejected the progress.
U.S. Special Envoy Steve Witkoff told reporters Sept. 24 that “we’re talking to [Iran]” but did not specify if he had met with Iranian officials. U.S. Energy Secretary Chris Wright told the IAEA Sept. 15 that the United States is still interested in reaching an agreement with Iran, but “Iran’s nuclear weapons pathway, including all enrichment and reprocessing capabilities, must be completely dismantled.”
Although the United States and Israel struck Iran’s two uranium enrichment facilities, a report from Le Monde suggested that Israeli intelligence assessed that Iran retains the capabilities to restart uranium enrichment. Iran says it will not agree to give up uranium enrichment as part of any deal.
The Kremlin’s proposal offered some hope but the United States had no immediate formal reaction.
October 2025
By Xiaodon Liang
Russia is “prepared to continue observing the … central quantitative restrictions” of the 2010 New Strategic Arms Reduction Treaty (New START) for one year after its expiration if the United States “acts in a similar spirit,” Russian President Vladimir Putin announced at a Sept. 22 Russian Security Council meeting.

New START, which limits U.S. and Russian nuclear forces to 1,550 strategic warheads and 700 strategic launchers deployed on each side, will expire Feb. 5, 2026. In 2021, the United States and Russia agreed to exercise a clause of the treaty permitting a one-time, five-year extension.
Speaking at a Sept. 22 news conference, White House Press Secretary Karoline Leavitt said the proposal sounded “pretty good.” Two weeks later, President Donald Trump, answering a question from a TASS reporter, affirmed the U.S. view, saying of Putin’s proposal, “it sounds like a good idea to me.”
U.S. Secretary of State Marco Rubio met with Russian Foreign Minister Sergey Lavrov Sept. 24 in New York on the sidelines of the United Nations General Assembly meeting. Although the two sides “compared their positions on the entire bilateral agenda,” according to the Russian statement summarizing the meeting, no progress was announced on arms control.
In extending the Sept. 22 offer, Putin said “a complete renunciation of New START’s legacy would, from many points, be a grave and short-sighted mistake” with “adverse implications for the objectives of the [nuclear Nonproliferation Treaty].”
Following the proposed one-year extension, Russia would make “a careful assessment of the situation [and] a definite decision on whether to uphold these voluntary self-limitations,” Putin said.
In his remarks, Putin did not say that an agreement, explicit or tacit—or even a U.S. announcement—was required before Russia would adopt its unilateral freeze. The measure would not be viable, however, if the United States takes “steps that would undermine or disrupt the existing balance of deterrence,” Putin said.
The Russian leader specifically named U.S. “preparations for the deployment of [missile defense] interceptors in outer space” as a step that could destabilize the strategic balance. (See ACT, September 2025.) Russia previously stated its concerns about the Trump administration’s plans for a comprehensive missile defense system, known as Golden Dome, in a May 8 joint statement with China. (See ACT, June 2025.)
A Chinese foreign ministry spokesman said Sept. 23 that his country “commends the positive stance” taken by Putin, before reiterating China’s standard rejection of Trump’s call for Beijing to take part in arms control negotiations alongside Moscow and Washington before the latter two make further substantial reductions in their arsenals.
Although Trump has not responded in public to the Russian proposal, he once again aired his skepticism of nuclear weapons in a Sept. 23 speech before the UN General Assembly.
“We want to have a cessation of the development of nuclear weapons,” the president said, noting that U.S. nuclear weapons “are so powerful that we just can’t ever use them.”
“If we ever use them, the world might literally come to an end,” he said.
But Trump has also previously said arms control talks with Russia might come only after the termination of the Russian full-scale invasion of Ukraine. (See ACT, September 2025.)
In a rhetorical shift following a Sept. 23 meeting with Ukrainian President Volodymyr Zelenskyy on the sidelines of the General Assembly, Trump said in a social media post that he believed Ukraine could restore its pre-2014 borders.
Although the president stopped short of offering further direct U.S. support for the Ukrainian war effort, he said the United States “will continue to supply weapons to NATO for NATO to do what they want with them.”
Zelenskyy, in his meeting with Trump, requested that the United States provide Ukraine with Tomahawk cruise missiles, The Telegraph reported Sept. 26. The Ukrainian leader confirmed at a Sept. 27 press conference that Ukrainian military experts would visit the United States in the coming weeks to negotiate a package of arms sales, valued close to $90 billion, that would be part of a post-conflict peace settlement.
The alliance responded to an incursion at an unprecedented scale since the start of Russia’s full-scale invasion of Ukraine in 2022.
October 2025
By Xiaodon Liang
NATO forces shot down Russian drones over Poland Sept. 10, responding to an incursion at a scale unprecedented since the start of Russia’s full-scale invasion of Ukraine in February 2022.

Twenty-one drones were detected in Polish airspace, flying primarily out of Belarus, according to Polish Prime Minister Donald Tusk. Polish and Dutch aircraft responded by shooting down at least three of the unmanned aircraft. No casualties have been reported in Poland, although falling debris—likely from a NATO air-to-air interceptor—damaged a house near Lublin.
Russian officials denied targeting the territory of Poland and implied that drones used in the war against Ukraine do not have the range to reach Polish targets.
But visual analysis of debris by multiple media outlets and Polish authorities confirm the aircraft are of Russian origin, likely Gerbera-type drones that can be equipped either as decoys or with explosive charges. The Gerbera is a derivative of the Iranian Shahed-136, which Tehran has supplied to Moscow in support of the latter’s war effort.
The chief of the general staff of Belarus’s military, Pavel Muraveiko, blamed the drone incursion on jamming by Russia and Ukraine. He claimed Belarusian forces had downed some stray drones before they reached Poland, and that his forces had exchanged information with Polish and Lithuanian counterparts.
NATO Secretary General Mark Rutte said the incursion was “reckless” and “unacceptable” regardless of Russian intentions, speaking Sept. 12 at a press conference.
The “Kremlin wanted to test the readiness of NATO allies,” Polish Foreign Minister Radoslaw Sikorski said Sept. 17 in a comment to Newsweek.
A joint statement issued Sept. 12 by Sikorski and his Lithuanian and Ukrainian counterparts directly accused Russia of a “deliberate and coordinated strike constituting an unprecedented provocation and escalation of tension.”
The drone incursion marked one of several Russian violations of NATO airspace in September. Three Russian MiG-31 combat aircraft entered Estonian airspace for 12 minutes in transit Sept. 20 toward Kaliningrad, and a sole Russian drone breached Romanian airspace Sept. 13, marking the eleventh similar incident according to data provided by the Romanian Ministry of Defense to ABC News. Individual Russian drones also have entered Polish airspace since the beginning of the Russian-Ukrainian war, the Polish Ministry of Defense noted Sept. 10.
Poland and Estonia requested consultations with NATO allies through invocation of Article 4 of the Washington Treaty, NATO’s founding agreement. On Sept. 12, Rutte and the supreme allied commander in Europe, Gen. Alexus Grynkewich, announced a new air defense mission for the alliance’s eastern flank, named Eastern Sentry.
According to Grynkewich, the new mission constitutes a “comprehensive and integrated approach” to air defense that would make it easier for NATO “to plug gaps in the line” where and when needed.
Invocations of Article 4 are rare but have increased since Russia seized Crimea in 2014. The last invocation of the treaty measure came in February 2022, after the beginning of Russia’s full-scale invasion.
At Poland’s request, the UN Security Council convened Sept. 12 to discuss the mass drone incursion.
The GAO finding calls into question previous statements by U.S. Air Force officials that the missile’s service life could not be extended.
October 2025
By Xiaodon Liang
The U.S. Air Force’s program office for the Minuteman III intercontinental ballistic missile (ICBM) has concluded that the strategic delivery system can remain in service through 2050, according to a Sept. 10 report by the Government Accountability Office (GAO).

That finding calls into question previous statements by Air Force officials that the service life of the missile could not be further extended. In 2021, the head of Strategic Command, Adm. Charles Richard, said there was “no more margin” to keep the Minuteman III in service.
The new GAO study, which is an unclassified version of an April 2025 report to Congress, says Air Force officials informed GAO that they now “are confident that Minuteman III can be used beyond 2030, even out to 2050.”
But those officials also acknowledged certain “unknowns such as ground electrical subsystems and electronics—for example, diodes, resistors, and capacitors—which could degrade to unacceptable levels.”
The report concluded that the Air Force has not “developed a risk management plan [for the transition from Minuteman III to Sentinel] or other risk management tools consistent with leading project management practices.”
The Sentinel ICBM was scheduled to begin deployment in 2029 and completely replace all 400 existing Minuteman III missiles by 2036. But a large increase in the projected costs of the Sentinel program forced the Air Force to reassess its plans, potentially adding several years of delay. (See ACT, September 2024.)
The GAO said that the Pentagon’s internal study of the large cost projection increase—mandated by cost control provisions of the Nunn-McCurdy Act—attributed the unanticipated problems to an unrealistic delivery schedule, ineffective systems engineering, and an incomplete basic system design, as well as an “atrophied” ICBM industrial base.
“Continuing to sink billions into a program that is behind schedule, over budget, and unproven when the existing program could last 25 more years is a waste of taxpayer dollars,” said Rep. John Garamendi (D-Calif.), a critic of the Sentinel program in a statement to Arms Control Today. In March 2024, Garamendi and Sen. Elizabeth Warren (D-Mass.) asked the Air Force to study the possibility of life-extending Minuteman III to 2030, 2040, or 2050.
A senior Air Force official claims that a new plan, finalized this summer to dig fresh silos for the Sentinel missile rather than reuse Minuteman III missile silos would speed up deployment and bring the Sentinel back toward its original deployment schedule.
Speaking at the Mitchell Institute Aug. 27, Lt. Gen. Andrew Gebara, the Air Force’s deputy chief of staff for strategic deterrence and nuclear integration, argued that, because building new silos would not require rotating Minuteman III missiles off-duty, more could be built at once and construction would therefore be more efficient.
The Air Force has argued that a full life-extension program for the Minuteman III would not be cost effective. Those arguments, however, hinged on the assumptions that an ICBM force would have to remain in service through 2075 and that a life-extension program would have to make significant replacements of major components of the missile system.
Last July, Gebara said the Pentagon had studied a service life-extension program for the Minuteman III as part of its mandatory review of the Sentinel following the Nunn-McCurdy breach.
“A long-term [service life-extension program] still does not make sense for Minuteman,” but “what is going to happen is Minuteman sustainment to keep it viable until Sentinel is delivered,” he said.
Air Force officials responsible for Minuteman III sustainment met in February to assess “end of life 2050” challenges, Bloomberg reported in March. The GAO now says the Minuteman III program will request funding for sustainment of launch facilities in forthcoming budget requests.
The report also revealed that Air Force Global Strike Command has already shifted the majority of non-deployed launch facilities to F.E. Warren Air Force Base in Wyoming, whereas previously they were spread across the three U.S. ICBM bases. To comply with the numerical caps of the New Strategic Arms Reduction Treaty, the United States keeps 50 non-deployed ICBM silos in a warm reserve status.
The Air Force confirmed that one Minuteman III silo at F.E. Warren Air Force Base had been taken offline recently as part of the transition to Sentinel, Breaking Defense reported Sept. 3.
According to the GAO report, the base’s 90th Missile Wing transferred control of a non-deployed launch facility to Global Strike Command’s Site Activation Task Force in April 2025 so that the task force could “validate work concepts” to provide information for the transition to Sentinel.
The weaponry, at a parade commemorating the 80th anniversary of the end of World War II, showcased China’s rapidly modernizing military power.
October 2025
By Shizuka Kuramitsu
China displayed its rapidly modernizing military power at a parade commemorating the 80th anniversary of the end of World War II, including unveiling its land-, sea-, and air-based nuclear triad for the first time.

The military parade in Beijing Sept. 3 was meant to “mark the hard-won victory in the Chinese People’s War of Resistance against Japanese Aggression and the World Anti-Fascist War,” according to the state Xinhua News Agency. It aimed to pledge “the country’s commitment to peaceful development in a world still fraught with turbulence and uncertainties,” the news outlet reported.
At the parade, China revealed one new intercontinental ballistic missile, the Dongfeng-61. This new missile was grouped with other nuclear systems—such as the Dongfeng-31-BJ ICBM; the sea-launched ballistic missile, Julang-3; and the air-launched ballistic missile, Jinglei-1—suggesting that the DF-61 is also nuclear, according to a Sept. 4 analysis by Hans Kristensen, Eliana Johns, Matt Korda, and Mackenzie Knight-Boyle of the Federation of American Scientists.
“Although only one of the nuclear weapons presented at the parade was entirely new (the DF-61 ICBM), that and the many other systems displayed in this and previous parades—combined with the construction of three large missile silo fields and so far more than a tripling of the nuclear warhead stockpile—vividly illustrate the significant modernization and buildup of nuclear forces that China has undertaken over the past couple of decades,” the federation team wrote.
Despite the public display of the DF-61 missile, it remains unclear how different it is from the existing Dongfeng-41 ICBM, according to the federation team report and Etienne Marcuz, associate fellow at the Foundation for Strategic Research, who commented Sept. 3 on X.
“Based on new information from the parade footage, it seems China now has nine different versions of land-based ICBMs: DF-5A, DF-5B, DF-5C, DF-27 (not yet displayed in public), DF-31A, DF-31AG, DF-31BJ, DF-41, and DF-61,” according to the FAS team.
The researchers said that the displayed buildup of nuclear forces “appears to contradict China’s obligations under the nuclear Nonproliferation Treaty and risks stimulating nuclear buildups in the United States and India—developments that would not be in China’s interest.”
Along with the land component, the Julang-3 and Jinglei-1 were displayed, marking the first-time that China has collectively showcased its full nuclear triad.
It also marked the first time that China displayed a nuclear weapons system for delivery by aircraft, the Jinglei-1, which was described by the official parade commentator as an “air-based long-range missile,” according to the FAS report. “This is likely the air-launched ballistic missile (designated CH-AS-X-13 by the [U.S. Department of Defense]) that the Chinese air force has been working on for several years to integrate on the H-6N intermediate-range bomber. The first bomber base to be equipped for the nuclear mission is thought to be Neixiang air base in Henan province,” added the FAS report.
According to the Sept. 3 Xinhua report, “Representatives … from countries such as Russia, the United States, the United Kingdom, France, and Canada” were invited to the event, which Chinese President Xi Jinping, Russian President Vladimir Putin, North Korean leader Kim Jong Un, and more than 20 other foreign leaders attended.
China’s People’s Liberation Army Rocket Force is responsible for overseeing the country’s conventional and nuclear land-based missiles. In 2023, the rocket force had several cases of corruption scandals that resulted in a large-scale purge. (See ACT, March 2023.) According to the Chinese-language Singaporean newspaper Lianhe Zaobao, Chinese media revealed Sept. 11 that the purge was a result of a nine-year-long investigation.
The investigation found that “procurement brokers with expert identities and state-owned enterprises that engaged in bid rigging, and their qualifications have been terminated,” the newspaper reported.
Leader Kim Jong Un said he is open to talks if Washington drops its demand for denuclearization.
October 2025
By Kelsey Davenport
North Korean leader Kim Jong Un rejected dialogue with South Korea, but said he was open to talks with President Donald Trump if the United States drops its demand for denuclearization.

Kim told North Korea’s parliament in a Sept. 21 speech that the country will “never ever” give up its nuclear weapons but will discuss “genuine peaceful coexistence” with the United States, according to a transcript published by the state-run Korean Central News Agency.
South Korean President Lee Jae-Myung suggested that Seoul would support talks aimed at freezing Pyongyang’s nuclear weapons program as an interim measure. Lee, speaking to BBC North Korea on Sept. 22, said South Korea cannot “give up on the long-term goal of [North Korean] denuclearization” but he acknowledged that a freeze would be a “feasible, realistic alternative” for now.
Lee first outlined a three-stage plan for denuclearization in August, beginning with a freeze. His administration provided more detail on its approach to North Korea in a Sept. 16 policy document. That document called for “institutionalizing peaceful coexistence” with North Korea.
Prior to releasing the new strategy, Lee met Trump in Washington at the White House. During their Aug. 26 press conference, Lee urged Trump to act as a “peacemaker” on the Korean peninsula. He said Trump is the “only person that can make progress” on resolving the North Korean nuclear weapons threat.
Trump expressed interest in holding another summit meeting with Kim “this year” and said he and Kim will “make relations better.”
It is unclear, however, if Trump would be willing to move away from denuclearization in order to engage Kim.
Trump met Kim three times during Trump’s first term. At the first meeting in Singapore in 2018, the two leaders signed a declaration committing the United States and North Korea to the complete denuclearization of the Korean peninsula. (See ACT, July/August 2018.) But the dialogue between the two leaders eventually broke down before North Korea took any tangible steps to dismantle its nuclear weapons program. North Korea is believed to have as many as 50 nuclear weapons.
The Trump administration has said little about its North Korea policy for its second term but suggested that any negotiations should take place based on the 2018 declaration. It appears unlikely, however, that Kim will agree to meet Trump if the U.S. goal is denuclearization.
High-level officials, including Kim, continue to describe the country’s nuclear weapons status as “irreversible.” North Korea may feel more emboldened to reject denuclearization after Kim traveled to China in September for meetings with Chinese President Xi Jinping and Russian President Vladimir Putin.
China previously expressed support for denuclearization of the Korean peninsula, but Xi did not mention denuclearization during his meetings with Kim. Russia already appears to have accepted North Korea’s nuclear status.
Strengthened ties with China and Russia also may reduce pressure on North Korea to improve ties with South Korea or the United States. During the Beijing trip, Kim appeared alongside Xi and Putin to view a military parade celebrating the 80th anniversary of the end of World War II.
KCNA said that Kim discussed “long-term plans” for cooperation with Putin and noted the special “friendship and alliance” between North Korea and Russia.
In addition to strengthening ties with China and Russia, North Korea continues to develop its domestic nuclear deterrent. North Korea announced Sept. 9 that it conducted the final ground test of a solid-fuel rocket motor designed for intercontinental ballistic missiles. According to the state-run Rodong Sinmun, Kim attended the test. The media outlet said the successful test “heralds a significant change in expanding and strengthening [North Korea’s] nuclear strategic forces.”
North Korea has already tested ICBMs capable of reaching the continental United States, but those systems were liquid-fueled. Solid-fueled ICBMs can be fired more quickly.
North Korea is developing a new ICBM, the Hwasong-20. It is likely the rocket motor that was tested is intended for that system. Kim visited the factory where North Korea is producing the Hwasong-20 on Sept. 2, according to KCNA. Kim said the new system will bolster North Korea’s strategic missile forces.
North Korea also appears to be processing plutonium from spent reactor fuel, likely for additional nuclear warheads. In a Sept. 8 statement, International Atomic Energy Agency Director-General Rafael Mariano Grossi said the agency has observed indicators since January 2025 that are “consistent with reprocessing irradiated fuel” from the 5-megawatt electrical reactor at the Yongbyon nuclear complex.
He also said that the IAEA observed via satellite imagery construction of a facility at Yongbyon that has “dimensions and features” similar to North Korea’s enrichment plant at Kangson. North Korea is known to enrich uranium, likely for nuclear warheads, but the full scope of the program is unclear.
Lee outlined the steps South Korea is planning to take in response to North Korea’s growing nuclear weapons program. In the Sept. 16 policy document, he said South Korea must strengthen its military capabilities in response to North Korea’s advances. Lee called for “independent deterrence” capabilities and said that South Korea would achieve that by strengthening its three-axis system and taking steps to modernize the military, including by improving and integrating drones and unmanned systems into the military and strengthening defenses against cyber threats.
The three-axis system is comprised of a “kill chain,” or preemptive strikes against North Korean missiles; “Korean Air and Missile Defense,” which is multilayered; and the “Korean Massive Punishment and Retaliation” campaign, which involves counterstrikes on Pyongyang in response to any attack and by targeting North Korean leaders.
The military is seeking vast numbers of cheap, disposable drones along with fewer highly capable but more expensive unmanned combat vehicles.
October 2025
By Michael T. Klare
In its drive to equip U.S. forces with increased numbers of unmanned weapons systems, the Department of Defense appears to be pursuing a “high-low” approach to procurement, seeking vast numbers of cheap, disposable drones along with fewer numbers of highly capable but more expensive unmanned combat vehicles.

The “low” end of this acquisition strategy was unveiled by Secretary of Defense Pete Hegseth July 10 in a memorandum to senior Pentagon officials on “Unleashing U.S. Military Drone Dominance.” As he indicated, the memo’s aim is to expedite the development, production, and deployment of low-cost drones in massive numbers.
“Drones are the biggest battlefield innovation in a generation,” Hegseth declared in the July 10 memorandum. Yet, “U.S. units are not outfitted with the lethal small drones the modern battlefield requires.”
To overcome this deficit, he called on the military services to rapidly commence large-scale purchases of such devices from U.S. manufacturers, including from start-up companies with little previous experience working with the Pentagon. “We will bolster the nascent U.S. drone manufacturing base by approving hundreds of American products for purchase by our military,”
he wrote.
To facilitate this process, Hegseth decreed in accompanying instructions that small drones, or unmanned aerial systems, be redefined as “consumable commodities” for procurement purposes, simplifying their acquisition by the military. “Small [unmanned aerial systems] resemble munitions more than high-end airplanes,” he stated. “They should be cheap, rapidly replaceable, and categorized as consumable.”
Apparently, on a separate track, the Pentagon and the military services are developing large, unmanned combat vehicles that are the very opposite of what might be termed “cheap, rapidly replaceable, and … consumable.” These include unmanned surface vessels the size of a small, manned corvette and pilotless jet fighters projected to cost tens of millions of dollars each.
In its budget request for fiscal year 2026, for example, the Defense Department sought $1.1 billion for procurement of the Medium Unmanned Surface Vessel, a pilotless, missile-armed warship with a projected length of up to 200 feet. The Navy already has tested several prototypes of the medium unmanned surface vessel, but it may be several years before production of combat-ready vessels will begin. (See ACT, November 2020.)
The 2026 Pentagon budget request also included $789 million for research and development of the Air Force’s Collaborative Combat Aircraft, an unmanned fighter jet intended to serve as a “loyal wingman” to piloted aircraft on high-risk missions. As envisioned by the Air Force, the collaborative combat aircrafts—each governed by AI-enabled flight controls—will be used to seek out enemy interceptors and air-defense systems and, when authorized by the pilot, engage them on their own.
In April 2024, Secretary of the Air Force Frank Kendall told members of a House Appropriations Committee subcommittee that the Air Force planned to acquire up to 2,000 of the unpiloted aircraft at an estimated cost of $25 million to $30 million each, a program that could cost as much as $60 billion. At that time, the service announced that it had chosen two nontraditional defense contractors, Anduril Industries and General Atomics, neither of which had previously received a major award of this size, to build prototype versions of the collaborative combat aircraft.
A contract award for production of combat-ready CCAs is not expected to be announced until sometime in 2026, but development of the two contending prototypes—General Atomics’s YFQ-42A and Anduril’s YFQ-44A—is proceeding apace. The prototype YFQ-42A underwent its first test flight on Aug. 27, and the YFQ-44A’s first flight is expected shortly, according to Inside Defense.
The Navy, too, has begun development of a collaborative combat aircraft-type “loyal wingman.” On Sept. 5, the service revealed that it had awarded contracts to four contractors—Anduril, Boeing, General Atomics, and Northrop Grumman—for “conceptual designs” for a carrier-based autonomous combat plane. Although expected to be similar in many respects to the Air Force’s collaborative combat design, the Navy variant will be designed to take off and land on aircraft carriers.
The U.S. is seeking to become the world’s premier drone provider instead of ceding that space to China or Turkey.
October 2025
By Shizuka Kuramitsu
The United States has decided to unilaterally reinterpret rules designed to control missile transfers so it can facilitate the sale of drones, the State Department announced Sept. 15.

In a statement, the department said that in order to “ensure predictable and reliable delivery of American products to foreign partners, and advance U.S. competitiveness abroad for unmanned systems [it] will now review requests to export [unmanned aerial systems] similar to how it reviews requests to export manned fighter aircraft.”
The new policy will make the United States “the premier drone provider instead of ceding that space to Turkey and China,” a U.S. official, speaking anonymously, told Reuters.
Under the policy, the Trump administration will reinterpret how the United States applies the guidelines set forth by the 1987 Missile Technology Control Regime, which is a voluntary export control regime involving 35 states that seeks to limit the proliferation of missiles and related technology that can carry weapons of mass destruction.
Under the MTCR, exports of Category I systems are subject to a “strong presumption to deny … transfers.” That category includes complete rocket systems and unmanned air vehicle systems that exceeds a range of 300 kilometers and a payload of 500 kilograms.
In a note to key congressional committees Sept. 3, the State Department noted that the change will enable it to “adjudicate foreign defense sales requests more efficiently, opening new markets for the U.S.”
It also asserted that U.S. export controls on missile technology “must keep pace with the speed and scope of technological developments, especially as the use of unmanned systems on the battlefield has become increasingly common for allies and adversaries alike.”
Reuters reported that this new interpretation of the MTCR “would unlock the sale of more than 100 MQ-9 drones to Saudi Arabia, which the kingdom requested in the spring of this year and could be part of a $142 billion arms deal announced in May.” By contrast, the United States “has not been selling or donating large drones to Kyiv for fear that advanced technologies could fall into enemy hands.”
President Donald Trump also revised the MTCR policy in 2020, during his first administration, to expedite sales of unmanned aerial vehicles. (See ACT, September 2020.) The new change “complements recent modifications to the national … MTCR-focused export policy under [the Biden administration’s] National Security Memorandum 28 and advances reforms made under the 2020 Revised UAS Export Policy,” a State Department factsheet said.
At the same time, the department emphasized the U.S. commitment to continue “to ensure its arms transfer review processes are implemented in a manner that does not contribute to the proliferation of weapons of mass destruction or their delivery systems,” and noted that the MTCR “remains an important component of U.S. national security policy.”