January/February 2025
By Shizuka Kuramitsu

China’s nuclear arsenal likely exceeds 600 operational nuclear warheads as of mid-2024, part of a diversified buildup that is projected to continue after 2030, the Pentagon said in its annual assessment of China’s military capabilities.

When compared to previous reports, “[w]e’re showing a rate of growth that is pretty well consistent with what we’ve described in reports over the past three years…about their nuclear expansion and modernization,” a senior U.S. defense official said at a press briefing on Dec. 18.

The spokesperson for the Chinese Defense Ministry, Zhang Xiaogang, told state-run Xinhua news on Dec. 21 that the intention of China’s nuclear weapons development is to “safeguard the country’s strategic security.”

“We urge the [United States] to stop fabricating false narratives, rectify the erroneous perception of China, and push for the healthy, stable development of bilateral and military relations,” he said.

The Pentagon’s annual report on China’s military power, published Dec. 18, covers developments through 2023. It repeats an estimate first made in 2021 that “China will have over 1,000 operational nuclear warheads by 2030” and will “continue growing its force through at least 2035.” But the report did not reiterate the projection published in 2023 that China aims to obtain 1,500 warheads by 2035. (See ACT, January/February 2023.)

When asked about removing that projection from the 2024 report and whether the previous projection still holds, the U.S. defense official said that “we think that [China] will continue growing their force to 2035 in line with the previous estimates.”

Given that 2035 is still more than a decade away, he said that “we’re still learning more, and [China] may be still defining for itself more of what basically completing [its] modernization means for 2035.”

“That could certainly change [China’s] perception of its strategic security environment, something that is always evolving and that they’re reassessing.… [B]ut I would certainly expect them to continue expanding the modernization [of] their force,” he added.

In general, this year’s report reaffirms previous assessments and adds specific timelines. For instance, the report says that China will implement a launch-on-warning posture “this decade.” Aligning with previous estimates that the Chinese nuclear arsenal is shifting from its historical posture of maintaining the capability to deal limited retaliatory damage, the report “suggests that [China] seeks to have the ability to inflict far greater levels of overwhelming damage to an adversary in a nuclear exchange,” including adopting a launch-on-warning posture and employing lower-yield nuclear weapons.

The report says that the Type 096 ballistic missile submarine (SSBN) “probably is intended to field” sea-launched ballistic missiles with multiple independently targetable reentry vehicles and “probably will begin construction in the mid-2020s,” a delay from last year’s estimate of “the early 2020s.” The Type 096 SSBN, China’s next-generation nuclear-powered submarine with longer-range sea-launched ballistic missiles, “will likely begin construction soon” and “is expected to enter service in the late 2020s or early 2030s,” the report says.

To support its nuclear force expansion, China has completed one of its two fast breeder nuclear reactors at Xiapu and construction on the other reactor continues, the Pentagon said. Hui Zhang, a senior research associate at Harvard University’s Belfer Center for Science and International Affairs, previously noted the development in an open-sourced assessment in Dec. 2023.

Confirming a leaked intelligence report from February 2023, the Pentagon assessed that China’s new Dongfeng-27 (DF-27) missile, which can be configured either as an intermediate-range or intercontinental ballistic missile, has a hypersonic glide vehicle payload option. Further, the report said that China “may have deployed” the DF-27 missile with this capability to its rocket force.

The report noted that China “largely denied, cancelled, and ignored recurring engagements and requests for communications” with U.S. officials until the November 2023 meeting between Chinese President Xi Jinping and U.S. President Joe Biden. Although bilateral tensions remain high, the Pentagon “is committed to maintaining open lines of communication with [Beijing] to ensure competition does not veer into conflict,” the report said.

It added that the U.S. Defense Department’s “objectives in maintaining military-to-military channels are to help prevent crisis, reduce strategic and operational risk, and clarify misperceptions.”

January/February 2025
By Xiaodon Liang

Congress asked the Defense Department to provide a path toward the potential expansion of U.S. nuclear forces in a defense policy bill unveiled in early December, but for now offered little additional money for programs beyond the nuclear sea-launched cruise missile.

Negotiators for the Senate and House of Representatives released a compromise $850 billion defense authorization bill for the 2025 fiscal year on Dec. 7 that rejected higher overall discretionary spending levels recommended earlier by the Senate Armed Services Committee. The total sum complies with fiscal limits adopted as part of a government spending agreement in 2023.

The House passed the defense authorization bill 281-140 on Dec. 11, and the Senate gave its approval 85-14 on Dec. 18. President Joe Biden signed the bill into law on Dec. 23.

The bill directs the Pentagon to provide congressional committees directly with an “assessment of the quantities and types of forces necessary” to hold at risk all the targets defined in the Biden administration’s nuclear weapons employment guidance, which was finalized this year. It also tasks the department to take into account “the planned growth in potential target quantities due to the expansion and diversification of likely adversary capabilities” over the next 10 years.

The bill, the key defense policy legislation, requires the department to report annually on implementation of the recommendations of the Congressional Commission on the Strategic Posture of the United States for the next five years. That commission, which released its final report in October 2023, called for increases in U.S. nuclear forces primarily through the expansion of existing modernization programs. (See ACT, November 2023.)

The bill also directs the Pentagon to provide plans to reduce the time needed to upload additional warheads to the existing intercontinental ballistic missile (ICBM) force, expand the future ICBM force to 450 deployed missiles, and manage the transition between older and in-development delivery vehicles.

Even as these directives lay the groundwork for future growth in U.S. nuclear forces, the bill provides full funding for the president’s current nuclear modernization budget requests across the board, trimming and adding only marginal amounts of money from accounts.

One notable exception is the budget for the increasingly expensive Sentinel ICBM. (See ACT, September 2024.) In the compromise defense bill, negotiators added $200 million to the program’s research and development effort to support prototyping and industrial-base risk reduction, bringing the program to an authorized limit of $3.9 billion infiscal 2025.

But the military construction budget for the missile was lowered significantly, with $366 million struck from a $680 million request for land acquisition and construction work at F.E. Warren and Vandenberg Air Force bases.

In July, the Pentagon announced that it would continue the Sentinel program despite continued projected cost increases. The department now estimates that the missile program will cost $141 billion in 2020 dollars. (See ACT, September 2024.)

The bill does not increase funding significantly for the Columbia-class ballistic missile submarine program beyond the $9.8 billion requested by the White House for shipbuilding and R&D.

But in votes on Dec. 20, Congress temporarily raised the annual budget for Columbia-class shipbuilding to $8.9 billion, up from the $5.8 billion approved in fiscal 2024 appropriations, in a second continuing resolution extending appropriations levels from the 2024 fiscal year. The higher spending rate will stay in place until fiscal 2025 appropriation levels are finalized. This additional funding for the Columbia program came as a response to a supplementary request from the White House in November.

The Office of Management and Budget, the Navy, and contractor Huntington Ingalls Industries have been involved in negotiations on the best way to pay for higher costs at the submarine shipyards in recent years, USNI News reported Nov. 25. According to the report, Chief Executive Chris Kastner of Huntington Ingalls noted “underlying realities: a tight fiscal environment, inflation, increased wage expectations for skilled labor, and extended supplier lead times.”

Months after the Biden administration dropped its opposition to a nuclear-capable sea-launched cruise missile, the defense bill adds $252 million for R&D for the program, up from $90 million appropriated last fiscal year. (See ACT, July/August 2024.) The bill also authorizes $70 million for the National Nuclear Security Administration (NNSA) to develop a warhead for the missile, maintaining funding constant compared with last year.

The Senate Armed Services Committee had recommended providing more money above the fiscal 2025 budget request to accelerate modernization of the Navy’s nuclear command, control, and communications system for ballistic missile submarines, which involves the E-6B Mercury aircraft. The final compromise legislation rejected this proposal.

The E-6B aircraft, a critical component in the communications chain between commanders and underwater submarines, is set to be replaced by a new aircraft, the E-130J, by 2026. Construction of the first airframe started in November, according to the Navy’s social media accounts, and the service awarded an overarching systems integration contract for the new plane on Dec. 18.

The compromise bill maintains funding for the B-21 bomber program at levels requested by the Biden administration in March, providing $5.3 billion for R&D and procurement. Speaking Dec. 6 at the Mitchell Institute, the head of the Air Force Global Strike Command, Gen. Thomas Bussiere, suggested that the service may seek to expand the number of bombers it buys beyond original plans for at least 100 aircraft. The total bomber fleet size “probably needs to be reevaluated based on the world as we see it today,” Bussiere said.

The prime contractor building the B-21, Northrop Grumman, told its investors earlier this year that its current fixed-price contract for low-rate initial production of the bomber would lead to $1.6 billion in pretax losses, spread over the first 21 aircraft. In June, the company said it had reached an agreement with the Air Force to raise the price of the plane under its next agreement for 19 more bombers. That threatens the Air Force’s initial promise to keep costs under $550 million per aircraft in 2010 dollars, which is now equal to $780 million.

The defense policy bill also provides $1.2 billion for continued upgrades to the B-52H bomber fleet, including $785 million for an engine replacement program. The new engine passed a critical design review in December, according to an announcement by contractor Rolls-Royce.

The bill adds $4.5 million for renuclearization of the 40 B-52H bombers that were configured for conventional missions to comply with the limits of the 2010 New Strategic Arms Reduction Treaty. Although the Senate committee had recommended directing the Air Force to begin renuclearization of the aircraft, the compromise bill permits renuclearization at the executive branch’s discretion.

Spending on nuclear programs remains largely in line with the president’s budget request, but congressional negotiators gave missile defense several notable boosts in the compromise defense bill. The defense committees authorized $393 million in additional spending on the Glide Phase Interceptor program, a U.S.-Japanese collaborative effort to produce an interceptor for bringing down hypersonic weapons with a glide trajectory.

In September, the Missile Defense Agency (MDA) selected Northrop Grumman to continue development of the interceptor, eliminating a competing design effort. In last year’s defense authorization act, Congress directed the agency to ensure that the interceptor can achieve initial operational capability by 2029, but agency leaders remain skeptical that goal can be met.

In its fiscal 2025 budget request, the Biden administration signaled that it would cease production of the Standard Missile-3 (SM-3) Block IB ballistic missile interceptor in favor of shifting toward producing the upgraded SM-3 Block IIA variant. The defense authorization bill reverses this decision, adding $250 million to restart SM-3 Block IB production and $65 million to expand SM-3 Block IIA production to 36 interceptors per year, up from the currently planned 12 per year. The Navy fired interceptors, including SM-3 missile variants, to defend Israel from Iranian ballistic missile attacks in April and October.

The defense bill also includes a requirement for the MDA to establish by 2031 a third Ground-Based Midcourse Defense site on the east coast of the United States. Proposals for the third site have been opposed by the Biden administration and failed in previous defense bill negotiations.

The bill also prohibits the NNSA from spending money on dismantling the B83-1 gravity bomb, a large-yield weapon that the Biden administration has sought to eliminate, without assurance from the head of Strategic Command that there are no “gaps” in the U.S. strategic deterrence posture. The Biden administration has argued that the new B61-13 gravity bomb would satisfy the hardened and large-area requirements previously met by the 1.2-megaton B83-1. (See ACT, December 2023.)

Congressional negotiators modified a restriction proposed by the House on data-sharing under the New Strategic Arms Reduction Treaty to permit unilateral disclosures when they would be in the national interest or if Russia were to resume providing notifications. The bill also includes a restriction on the admittance of Chinese and Russian citizens to the national laboratories after April 15, 2025.

In an organizational move, the bill designates the assistant secretary of defense for nuclear, chemical, and biological defense programs as the principal civilian adviser to the defense secretary for nuclear programs and policies, including “all matters relating to the sustainment, operation, and modernization of United States nuclear forces.”

Defense Secretary Lloyd Austin noted his concerns with this modified position in a Sept. 26 letter to the congressional defense committees, stating that the reorganization threatened to “carve out functions and authorities” from two existing offices, that of the undersecretary for acquisition and sustainment and the undersecretary for policy, creating “unclear lines of authority.” The final legislation clarifies the original Senate proposal by stating that the new assistant secretary will advise and assist the existing undersecretaries.

Negotiators significantly changed a House recommendation that Congress mirror the Biden administration’s language that a human always should remain “in the loop” on critical nuclear weapons employment decisions.

Instead, the compromise version states that it is U.S. policy that the use of artificial intelligence in nuclear forces should not compromise “the principle of requiring positive human actions in execution of decisions by the President with respect to the employment of nuclear weapons.”

January/February 2025
By Mina Rozei

International experts have stepped up their monitoring of chemical weapons stockpiles in Syria since the overthrow of President Bashar Assad, but there is much uncertainty about the status of the program and possible contamination due to strikes on military facilities there, according to UN and U.S. officials.

At an emergency meeting of the Executive Council of the Organisation for the Prohibition of Chemical Weapons (OPCW) on Dec. 12, Director-General Fernando Arias reported on “airstrikes targeting military facilities” after Assad was ousted four days earlier by Syrian rebels and fled to Moscow.

“We do not know yet whether these strikes have affected chemical weapons-related sites,” but they “could create a risk of contamination,” Arias said. Multiple news media reported that the Israel Defense Forces began a bombing campaign that included suspected chemical storage sites almost immediately after Assad was ousted.

Arias noted that Syria’s political and security situation “remains volatile.” He warned that attacks on chemical sites also could risk “the destruction of valuable evidence” needed for investigations by various independent international bodies probing the Assad regime’s use of chemical weapons and risk “dangerous chemicals or equipment being lost, without any control.”

Along with the OPCW, the United States has been waiting to see if remnants of the Assad regime’s chemical weapons stockpiles would be found, but The New York Times reported on Dec. 25 that “none are known to have turned up so far.”

In a speech on Dec. 19, U.S. Deputy National Security Advisor John Finer said that the United States was making the future of the Syrian chemical stockpile a priority after Assad’s fall and would work with the OPCW and states in the region to find, secure, and dispose of any remaining chemical weapons stockpiles.

He also said that the United States understands that the Syrian rebel group Hayat Tahrir al-Sham (HTS) and the caretaker government in Damascus are committed to recovering and disposing of chemical stockpiles and that Washington has encouraged them to do so.

The fall of the Assad regime raises important questions about the remainder of Syria’s chemical weapons stockpile.

For 11 years, the OPCW has worked to persuade Syria to fulfill its obligations under the Chemical Weapons Convention (CWC) by coming clean about its chemical weapons program and destroying all components. Instead, the Syrian government obfuscated and delayed releasing a full report of its chemical program.

Arias said that, since Assad’s ouster, the OPCW has heard “positive signals from within Syria” on the need to rid the country of chemical weapons but “to date, we have not received any official request for help from any Syrian authorities.”

In a Dec. 9 statement, the OPCW “reaffirm[ed] its commitment to clarifying gaps, discrepancies, and inconsistencies in Syrian chemical weapons declarations amidst [the] political transition.” The statement said that the OPCW Technical Secretariat communicated with the Syrians to “ensur[e] the safety and security of all chemical weapons[-]related materials and facilities at all locations on [Syrian] territory.”

At high-level meetings since 2022, top UN disarmament officials bemoaned the “gaps, inconsistencies, and discrepancies” in Syria’s declaration regarding its use of chemical weapons, which the United Nations considered incomplete and not in accordance with the CWC.

Syria acceded to the CWC in September 2013 after allegations of chemical weapons use by the Assad government. The Technical Secretariat formed the Declaration Assessment Team in 2014, when Syria first submitted its declaration to the OPCW. The OPCW repeatedly has questioned the accuracy and completeness of the declaration, stalling the verification of Syria’s chemical weapons stockpile and its eventual destruction.

The OPCW confirmed that there were 'reasonable grounds' to believe that the Syrian military used chemical weapons on Douma in 2018. (See ACT, March 2023.)

The OPCW also confirmed the use of chemical weapons by nonstate actors in 2015. Numerous other cases of chemical attacks took place during the Syrian civil war in 2013-2024, but no perpetrator has been determined. (See ACT, April 2024)

January/February 2025

Congress once again failed to allocate aid for communities harmed by U.S. nuclear weapons testing and development in its latest federal spending bill.

The Radiation Exposure Compensation Act (RECA), established in 1990, provided one-time payments to downwinder communities affected by Cold War-era nuclear testing, uranium mining, and nuclear waste. Nuclear justice advocates for decades have challenged the program’s restrictive eligibility criteria and pushed for its extension and expansion. The program expired in June without any adjustments. Since then, advocates have been trying to reinstate it through various legislative vehicles. (See ACT, July/August 2024.)

On Dec. 17, Sen. Mike Lee (R-Utah) said that House Speaker Mike Johnson (R-La.) has “blocked” RECA reauthorization from being included in the continuing resolution, an interim bill to keep the government running without regular appropriations. Sen. Josh Hawley (R-Mo.), another proponent of RECA, blasted Johnson on Dec. 17 on the social platform X for “personally killing a bipartisan, bicameral expansion bill” while spending “billions on Ukraine and foreign wars.”

In his post, Lee said that he had worked with other lawmakers, including Rep. Celeste Maloy (R-Utah), Sen. Kyrsten Sinema (I-Ariz.), and Hawley, to get a “compromise measure” for RECA. Lee did not explain what was included in the compromise and whether it reflects the expansion and extension bill that the Senate approved last year. (See ACT, September 2024.)—SHAGHAYEGH CHRIS ROSTAMPOUR

January/February 2025

The director-general of the International Atomic Energy Agency (IAEA) condemned the drone strike on an IAEA vehicle at Ukraine’s Zaporizhzhia Nuclear Power Plant on Dec. 10.

The attack took place as the vehicle and its driver were leaving the site to collect members of the team that was completing the 26th rotation of personnel for the IAEA support and assistance mission to Zaporizhzhia. There were no injuries. The strike took place within Ukrainian-controlled territory approximately 8 kilometers from the frontline with invading Russian forces, according to an IAEA statement.

Speaking at the IAEA Board of Governors meeting on Dec. 12, Director-General Rafael Mariano Grossi said that the drone was a “so-called loitering munition which is designed to explode on impact. As a result, there is no discernible debris to be recovered.”

He reminded the international community to exercise “the maximum restraint” and avoid “pointing fingers” because there are not “irrevocable and definite elements” to identify the attacker after much of the drone evidence was destroyed.

In a post on the social platform X, Ukrainian President Volodymyr Zelenskyy blamed Russia for the strike. “The Russians could not have been unaware of their target; they knew exactly what they were doing and acted deliberately,” he wrote. “This attack demands a clear and decisive response…. Silence or inaction will only embolden further violations.”

On Nov. 7, Grossi commented on the 25th support and assistance mission to Ukraine, saying, “We will stay at these sites for as long as it is needed to help avert the threat of a nuclear accident that could have serious consequences for human health and the environment in Ukraine and beyond. As the nuclear safety and security situation remains highly challenging, our experts are continuing to play a crucial stabilizing role at all these facilities.”

That message has not changed since the attack. As Grossi briefed the IAEA board, he reaffirmed that, “[o]n our own will, we will not cease our operation. We will continue there.”

The IAEA has been on the ground at Zaporizhzhia since September 2022 when Grossi led the first support and assistance mission to the nuclear complex.—LIBBY FLATOFF

January/February 2025

Japan and the United States announced their first guidelines for strengthening U.S. extended nuclear deterrence, saying they face “an increasingly severe strategic and nuclear threat environment.”

“This document reinforces the alliance’s existing consultation and communication procedures related to extended deterrence,” the two countries said in a joint announcement on Dec. 26. “The guidelines also address strategic messaging to maximize deterrence and enhance measures for U.S. extended deterrence, bolstered by Japan’s defense capabilities.”

The two sides have not made the guidelines public or otherwise provided details about what has been agreed.

But Yomiuri Shimbun, citing anonymous Japanese officials, reported on Dec. 29 that the guidelines include provisions that Japan and the United States will communicate regarding the use of U.S. nuclear weapons through the Japanese Self Defense Force’s alliance coordination mechanism. The guidelines document is the first one to articulate Japan’s involvement in U.S. decision-making on nuclear use, according to the news report.—SHIZUKA KURAMITSU

January/February 2025
By Daryl G. Kimball

In recent years, significant attention has been focused rightly on the dangers posed by a three-way nuclear competition among China, Russia, and the United States and their failure to engage in meaningful diplomacy to halt and reverse the nuclear arms race as required by the nuclear Nonproliferation Treaty (NPT).

At the same time, simmering tensions between nuclear-armed China and India and between NPT outliers India and Pakistan also are driving a triangular nuclear arms race that has exacerbated the risks of nuclear escalation and missile proliferation.

At a December forum co-hosted by the Arms Control Association, U.S. Deputy National Security Advisor Jon Finer said that Pakistan, which was granted “major non-NATO ally” status in 2004, is pursuing “increasingly sophisticated missile technology” that eventually could enable the country to “strike targets well beyond South Asia, including the United States.”

According to senior U.S. officials, Pakistan has sought for several years to increase the range and throw-weight capabilities of its medium-range ballistic missiles with help from entities in Belarus and China. They say Islamabad could have a long-range missile capability of greater than 3,000 kilometers “within a decade.”

The officials, who briefed me and other nongovernmental experts on Jan. 3, said that Pakistan turned down U.S. proposals for confidence-building measures. They explained that new U.S. sanctions on a Pakistani state enterprise and commercial entities in Belarus and China that are supplying missile-applicable equipment to Pakistan are designed to slow the program.

In response, Pakistani officials called Finer’s comments “devoid of rationality” and said that their country “has never had any ill-intention towards the United States.” Pakistan’s nuclear capabilities “are solely meant to deter and thwart a clear and visible existential threat from our neighborhood,” they said.

But the notion that long-range missiles are needed to deter Pakistan’s neighbor and nuclear rival, India, is specious. Pakistan's Shaheen-III ballistic missile, which was first tested in 2015 and has a range of 2,750 kilometers, already gives Pakistan the ability to strike any target in India.

With 170 plutonium-based nuclear warheads on short- and medium-range systems, Pakistan already has enough nuclear firepower to deter a nuclear attack from India and obliterate much of the subcontinent. The country continues to produce fissile material and retains the option to use nuclear weapons first against non-nuclear military threats.

Since 2012, India has developed and tested the Agni-V intercontinental ballistic missile (ICBM), which is capable of delivering multiple warheads at a distance of 5,000 kilometers and puts all of China within range of a devastating nuclear attack. But unlike India, there is no coherent nuclear deterrence rationale for Pakistan, an ally of China, to possess long-range missiles. For these and other reasons, Finer said, “[I]t is hard for us to see Pakistan’s actions as anything other than an emerging threat to the United States.”

The renewed U.S. attention to Pakistan’s advancing missile capabilities and targeted sanctions are warranted and overdue but insufficient. Over the years, Republican and Democratic administrations have been frustratingly inconsistent in their nonproliferation goals pertaining to India and Pakistan as they prioritized other aspects of bilateral relations. As a result, India continues steadily developing more advanced nuclear systems while Pakistan produces more fissile material and new missile capabilities in the name of “full spectrum deterrence” against India.

In response, leaders in Washington and other capitals need to implement a more comprehensive and balanced strategy based on the reality that the possession and buildup of nuclear weapons by any state, friend or foe, is a danger to international peace and security.

The new Trump administration should press forward with missile-related sanctions and engage with Pakistan regarding its long-range missile program. The administration also should press India to consider self-imposed limits on its ICBM capabilities, including a ban on multiple warhead missiles, which Pakistan may view as a threat to its nuclear retaliatory potential. The administration also should work with other key governments to encourage Indian and Pakistani leaders to restart their moribund nuclear risk reduction and arms control dialogue.

Washington and its allies should also elevate global diplomatic efforts to bring into effect a long-sought halt in global fissile material production, which China and Pakistan have resisted for years. At the same time, the United States and Russia need to reach an interim deal not to expand their own strategic nuclear forces following the expiration of the New Strategic Arms Reduction Treaty in 2026. Failure to do so would undermine U.S. calls for restraint by others and give China further motivation to increase its ICBM force, which in turn would stimulate Indian and Pakistani missile advances.

At this point, Pakistan seems determined to proceed with its long-range missile program. But with time, sustained, serious dialogue, and a more balanced approach, the next administration may find opportunities to reduce nuclear and missile threats in Asia that so far have eluded U.S. policymakers.

January/February 2025 
By Walter Slocombe

Observers as different as Soviet leader Leonid Brezhnev and U.S. National Security Advisor Zbigniew Brzezinski agreed that President Jimmy Carter had a deep personal commitment to arms control as a means of reducing the risk of nuclear war. That commitment was based on Carter’s moral principles and religious faith, his experience as an officer in the nuclear navy, and his understanding of the horror of nuclear war. He hoped for the ultimate abolition of nuclear weapons, but accepted that arms control was a necessary stage toward that end. Carter, who died December 29 at the age of 100, repeatedly said that arms control was his top priority as president.

The Carter administration launched efforts on multiple fronts: nuclear proliferation, nuclear weapons testing, arms sales, restraint on technological advances, nuclear-weapon-free zones, pullbacks of some U.S. nuclear deployments around the world, and restrictions on nations from outside the region deploying their military forces to new regions, such as the Indian Ocean. These efforts, including Carter’s attempts to negotiate an expanded ban on nuclear testing and to block a neutron bomb, had various degrees of success and controversy, but his main focus was endeavoring to impose limits on strategic forces, and that was the arms control issue in which he was most involved. Although the treaty that he negotiated under the Strategic Arms Limitation Talks (SALT) was not ratified, it was, from the perspective of priority and personal involvement, his biggest national security success apart from the Egypt-Israel peace agreement.

From the moment Carter assumed office in 1977, he hoped to take dramatic steps beyond the initial 1972 agreements on offensive nuclear weapons and missile defenses achieved by President Richard Nixon and beyond the tentative arrangements that his immediate predecessor, President Gerald Ford, and Secretary of State Henry Kissinger had worked out with the Soviet Union at the Vladivostok arms control summit in 1974. Carter was convinced that, for all their other faults, Brezhnev and the rest of the Soviet leadership recognized the essential need to confront the nuclear danger.

Accordingly, Carter believed that a comprehensive, far-reaching U.S. initiative at the start of his administration would appeal to the Kremlin and instructed his new team to develop a proposal to achieve that end. He clearly hoped that the Soviets were open to dramatic action. After all, Kissinger, the architect of the Nixon-Ford arms control agenda, had been briefed on the general thrust of Carter’s initiative and, with characteristic ambiguity, had told the president that the Soviets might agree.

Within a few weeks, Carter had settled on offering the Soviet leaders a choice. His much-preferred option sought agreement on significant cuts below the level that had been decided tentatively at Vladivostok and on expansion of the scope of the limitations to include constraints on heavy missiles as the weapons having the most dangerous potential for attempting a disarming preemptive strike. He also offered the alternative of a quick agreement along the lines of the U.S. position at Vladivostok.

When Secretary of State Cyrus Vance presented these proposals in Moscow in May 1977, however, the Soviets bluntly rejected both options. The deep cuts apparently were too ambitious, and the limited step was viewed as repudiating a consensus that the Soviets claimed was settled definitively at Vladivostok. Carter decided not to permit his negotiators to advance a fallback position that he had approved for use in Moscow if the Soviets had proved ready to engage immediately in serious negotiations.

Afterward, Carter was widely criticized for thinking that the cautious and sclerotic Soviet leadership would jump at a chance for rapid steps forward. The media, well-organized political opponents of the arms control process, and some experts proclaimed the imperilment, if not the end, of negotiations on strategic nuclear weapons. In fact, in the face of overwrought media and opposition scorn for his substantive proposals and his supposed naivete, inexperience, and overambition, Carter quickly accepted that an agreement would require more time and painstaking negotiation.

Within a few weeks, he had the process back on track. Complex negotiations over many months thereafter were complicated by the fact that although his senior advisers accepted and supported the broad goal of a SALT II agreement, Vance and Brzezinski had distinctly different views on where the agreement fit in the overall U.S. relationship with the Soviet Union. This concept came to be called “linkage.” Vance viewed an agreement as being as much in U.S. interests as it was in Soviet interests—useful not only on its own terms but as an essential building block for a general improvement in U.S.-Soviet relations. Brzezinski, while genuinely supporting pursuit of an agreement, believed that the Soviet Union needed a deal more than the United States did and therefore the United States had leverage for conditioning progress on SALT II on moderation of Soviet conduct more generally.

The linkage debate between the contrasting arms control views of the two senior advisers was exacerbated further by their differences on the normalization of relations with China, which were moving toward implementation just as the SALT II negotiations neared culmination. Although both men supported normalization in principle, Brzezinski saw it as a means to present the Soviet Union with the specter of a de facto U.S.-Chinese alliance. Vance, by contrast, feared that taking that major diplomatic step toward China with SALT II still unresolved would reduce the Soviet willingness to negotiate.

In this regard, Carter was wiser than his advisers. Rather than adopt either view, he recognized that both goals, an agreement on SALT II and prompt normalization with China, would serve U.S. security. He rightly judged that Soviet interest in calming the bilateral strategic nuclear relationship would limit the Kremlin’s reaction to normalization with China. Carter declined to attempt to use two military projects that he had already decided to disapprove, the B-1 bomber and the neutron bomb, as bargaining chips, but he ensured that the United States responded to Soviet actions that posed a danger to its national security interests. For this reason, he chose to conduct the SALT II negotiations independently of other issues while taking steps to respond to Soviet challenges and enhance U.S. military capabilities. These steps included increasing the national defense budget and seeking, with some success, to persuade allies to do the same.

The budget increases funded such defense innovations as the development of stealth technology and the acquisition of other new conventional systems, such as stealth aircraft, highly accurate ground ordnance, and sea- and air-launched cruise missiles that formed the backbone of U.S. capabilities for a generation. Carter also implemented an ambitious program of modernization of each element of the U.S. deterrent force, including cruise missiles for bombers, the new D-5 missile for submarines, and a new land-based MX missile to be based in such a way as to be invulnerable to preemptive attack.

He rejected the idea of adopting a no-first-use of nuclear weapons policy as weakening deterrence and launched a program to deploy ground-launched nuclear missiles in Europe as a response to Soviet deployment of the new SS-20 missile, which had a range below the SALT threshold but was sufficient to reach most of Europe. It is a measure of Carter’s understanding of his unique responsibility as commander in chief of the U.S. nuclear arsenal that he oversaw a reshaping of the basic principles guiding nuclear doctrine and planning and gave unprecedented attention to the operational aspects of procedures for deciding on and, if necessary, shaping any actual use of nuclear weapons.

Domestically and internationally, Carter’s arms control efforts faced political obstacles as formidable as the Soviet negotiators. The Cold War context was hardly conducive to cooperation with the Soviet Union. The U.S. failures in Vietnam raised questions among allies about U.S. will, judgment, reliability, and capability. Carter’s term coincided with the era of Soviet proxy campaigns in places such as Angola, Nicaragua, Somalia, and Yemen. It did not help that these adventures were often executed on behalf of Moscow by Cuban leader Fidel Castro.

Moreover, since the mid-1960s, the Soviets had carried out a rapid catch-up strategic force expansion that, by some limited criteria, exceeded U.S. levels and with various degrees of plausibility could be portrayed as threatening the survivability of U.S. land-based forces. These factors not only made bilateral talks difficult, but they also fueled doubt among the U.S. public about agreeing with Moscow about anything, including arms control.

At home, Carter faced criticism over the terms and details of negotiations with the Soviets and often an outright denial of the basic value of arms control generally and the SALT II negotiations specifically. U.S. Senator Henry “Scoop” Jackson (D-Wash.) and longtime prominent Democratic defense figure Paul Nitze, perhaps the most vocal and well informed of the critics, had backers in Congress, the media, think tanks, and some elements of the defense industry and the retired military officer corps. Although some Republicans supported Carter’s efforts, the Republican Party institutionally had an interest in portraying the Democratic administration as weak and incompetent. On Carter’s own side of the political divide, several important Democratic members of Congress, some peace activists, and national security experts seemed willing to regard any plausibly negotiable deal as inadequate while others were lukewarm at best. Moreover, some Democratic senators ostentatiously demonstrated their independence from an unpopular president with exaggerated skepticism about elements of his centerpiece security agenda.

Faced with this difficult environment, Carter and his team recognized that getting the SALT II treaty ratified by the Senate would be as great a challenge as negotiating it with the Soviets. An absolutely necessary condition for Senate approval of a treaty, although by no means a sufficient one, was its validation by senior military leadership. To this end, Secretary of Defense Harold Brown, for whom I lead the SALT II staff in the Office of the Secretary of Defense, and Joint Chiefs of Staff Chairman General David Jones managed to avoid getting entangled in the Vance-Brzezinski linkage debate. Their priority for substantive and ratification reasons was negotiating an agreement that served to reduce nuclear risks and protect Department of Defense equities, in the sense of not foreclosing potentially important U.S. strategic programs and of ensuring that the Joint Chiefs of Staff would unequivocally endorse whatever emerged from the negotiations. The Joint Chiefs of Staff duly endorsed the treaty as “modest but useful.” Some wag observed that not much in Washington exhibits both those characteristics.

Carter may have been overly optimistic about rapidly resolving all the details, but what was ultimately agreed, in addition to defining treaty terms and obligations with unprecedented precision, accomplished much of what was in his original proposal. These included top-line aggregate numbers that were lower than the ones discussed at Vladivostok, sublimits on heavy missiles and missiles with multiple independently targetable reentry vehicles, a range of limits on new missiles and on modernization, meaningful controls on cruise missiles while preserving critical U.S. programs, and a prohibition on concealment measures that impede verification, such as encryption of missile test data. Carter oversaw the arcane negotiation of technical details and often had to resolve differences within the administration. His intense personal participation culminated when, in the final day before signing the treaty, he secured a personal assurance from Brezhnev on the production rate for the Soviet Backfire bomber, whose status had been in contention from the beginning of the process at Vladivostok.

Even without linkage and with relatively early agreement on numerical limits, the negotiations were protracted. Final agreement came only in June 1979, worryingly close to the 1980 presidential election. The administration, with Carter in the lead, had sought to keep senators informed of the status of the talks as a way to lay the foundation for ratification. Prolonged Senate hearings addressed a wide range of issues, from the obscure to the fundamental and from the serious to the pretextual.

Although the opposition to ratification was relentless and the good faith concerns of many senators required painstaking explanation, Carter was ready by late 1979 to bring the treaty up for a Senate vote because he was cautiously optimistic that he had the necessary 67 votes. The Soviet invasion of Afghanistan in December 1979, however, destroyed any possibility of ratification on that timetable. Iran’s seizure of the U.S. Embassy in Tehran and the taking of 52 American hostages destroyed whatever prospect there may have been to restart the ratification campaign during the last year of Carter’s term. His defeat by Ronald Reagan denied him a second term and the opportunity to move toward a SALT III agreement with even more far-reaching constraints.

It was a bitter disappointment for Carter that the SALT II treaty did not come into legal effect, but that did not mean the failure of Carter’s effort. The Soviet regime and the Reagan administration complied with most SALT II provisions. The framework of numerical and qualitative limitations that the treaty established provided the foundation for future agreements over the next several decades. Carter’s dedicated labor for arms control is a proud and consequential component of his legacy.

Walter Slocombe led the Strategic Arms Limitation Talks (SALT) task force in the Office of the U.S. Secretary of Defense during the SALT II negotiations and later was undersecretary of defense for policy.