Russia, the CTBT, and International Law

November 2023
By David A. Koplow

The recent decisions by the Russian Duma regarding the 1996 Comprehensive Test Ban Treaty (CTBT) have generated considerable legal and policy confusion. This analysis is an attempt to clarify the nature and consequences of those actions under international law.

Russia’s process is not an exercise of the “supreme national interests withdrawal clause,” which is contained in article IX of the CTBT and is common in other arms control agreements. That provision, like the rest of the treaty, is not operational until the treaty enters into force, which has not occurred. Article IX cannot be relied on by any state under the current circumstances and is not the basis for Russia’s recent actions.Instead, the next reference point is the 1969 Vienna Convention on the Law of Treaties, which sets forth the provisions regarding the conclusion, operation, and interpretation of international agreements. Article 18 of the convention establishes two circumstances under which a state is obligated to “refrain from acts which would defeat the object and purpose of a treaty” before the treaty enters into force.

The exact scope of the CTBT’s “object and purpose” is debatable. In 2016 the five nuclear-weapon states recognized under the nuclear Nonproliferation Treaty, which are also the permanent members of the UN Security Council (China, France, Russia, the United Kingdom, and the United States), issued a joint statement in which they authoritatively affirmed that a nuclear test would defeat the CTBT’s object and purpose. The entire Security Council subsequently endorsed that interpretation in Resolution 2310.

The first circumstance in which this obligation is operational is detailed in Vienna Convention article 18(a), which addresses the interval between a state signing and ratifying the treaty. That is the situation in which China, the United States, and a few others now stand regarding the CTBT. This obligation applies until the state “shall have made its intention clear not to become a party to the treaty.”

The mechanism for a state to specify its intention not to ratify a treaty, often incorrectly referenced as “unsigning” the treaty, is what the United States exercised regarding the 1998 Rome Statute establishing the International Criminal Court and the 2013 Arms Trade Treaty. In those cases, by expressing the intention not to ratify, the United States was released from the obligation to refrain from acts that would defeat the object and purpose of those treaties.

Russia has ratified the CTBT, so its recent actions are not governed by article 18(a). Instead, article 18(b) provides the same obligation to refrain from acts that would defeat the treaty’s object and purpose during the interval between ratification and the treaty’s entry into force “provided that such entry into force is not unduly delayed.”

In principle, a state perhaps could declare  that the CTBT’s entry into force has been “unduly delayed.” The treaty was opened for signature in 1996, but is unlikely to enter into force in the foreseeable future. Yet, Russia has not cited “undue delay.” Instead, it complained about the U.S. failure to ratify the CTBT and activities at the U.S. nuclear test site. Hence, the convention does not provide the mechanism for Russia to “unratify” the CTBT.

State practice regarding other treaties has rarely been tolerant of a withdrawal of a ratification prior to the treaty entering into force. The secretary-general of the United Nations, the usual depositary for multilateral treaties, occasionally has allowed a state to rescind a ratification without reference to or authorization by the convention. That presumably is what would happen here.

The final piece of the puzzle turns back to article 18(a) and raises the question of whether Russia’s withdrawal of its CTBT ratification also should be treated as an expression of an intention not to ratify the treaty again in the future. If so, the Duma’s action also could be interpreted as an “unsigning” of the CTBT, releasing Russia from the obligation to refrain from acts that would defeat the treaty’s object and purpose. More likely, the withdrawal of Russia’s ratification would not be interpreted as carrying that double effect, so Russia still would be regarded as a CTBT signatory obligated under article 18(a). That interpretation is reinforced by Putin’s comments about seeking “parity” with the United States regarding the CTBT; both states would now be obligated to refrain from acts that defeat the treaty’s object and purpose, including the obligation not to conduct nuclear tests.

In sum, Russia’s withdrawal of its CTBT ratification is not contemplated by the CTBT or the Vienna convention. Yet, it is an accepted, rare practice under international law. Russia thereby will achieve its objective of mirroring the United States regarding each country’s status under the treaty.

The withdrawal of ratification most likely has no practical legal effect. Russia, like the United States, would still be obligated as a signatory to refrain from acts that would defeat the treaty’s object and purpose, including nuclear testing. To date, Russia has not indicated any intention to violate its obligation under the convention by terminating its national moratorium.

David A. Koplow is the Scott K. Ginsberg Professor of Law at the Georgetown University Law Center.