UNSCR 2310 and the CTBT: Some Thoughts

I’ve been meaning for a while now to comment briefly on the adoption by the Security Council of Resolution 2310 on September 23, 2016.  In this resolution the Council addresses the subject of nuclear weapons testing and the Comprehensive Test Ban Treaty. The CTBT was opened for ratification in 1996, and to date 166 states have ratified it.  However, the treaty has not come into force because the treaty text provides that entry into force will only occur when all of the states listed by name in Annex 2 of the treaty have ratified it.  Currently eight of those Annex 2 states – China, Egypt, India, Iran, Israel, North Korea, Pakistan, and the United States – have still not ratified the treaty.

In the lead up to the adoption of Resolution 2310 there was a lot of speculation that the resolution would be adopted under the Council’s Chapter VII powers, and that it would use legally mandatory language to establish a universal ban on nuclear weapons testing.  In the U.S., in particular, this prospect was met with considerable opposition in some quarters.  The argument was made that the Obama administration was trying to undermine the constitutional power of the U.S. Congress by essentially going over its head to the UN Security Council to establish an internationally legally binding rule prohibiting testing – this notwithstanding the Senate’s rejection of U.S. ratification of the CTBT as a treaty in 1999.

As it turned out, Resolution 2310 was not in fact adopted under Chapter VII and there is no legally mandatory language used in the resolution.  Thus the resolution does not create any new legally binding rule of international law. Apparently this is due to push back from Russia and China in the drafting of the language.

The resolution does inter alia mention the joint statement made by the five NPT nuclear weapons states on September 15, 2016, in which they recommitted themselves to their previously announced unilateral moratoria on nuclear weapons testing, and further recognized that “a nuclear-weapon test explosion or any other nuclear explosion would defeat the object and purpose of the CTBT.”

This language about the object and purpose of the CTBT was pretty clearly intended to reference Article 18 of the Vienna Convention on the Law of treaties. Article 18 provides in part that:

A State is obliged to refrain from acts which would defeat the object and purpose of a treaty when:

(a) it has signed the treaty or has exchanged instruments constituting the treaty subject to ratification, acceptance or approval, until it shall have made its intention clear not to become a party to the treaty;

This language in the NWS joint statement can be read to particularly address the situation of states which have signed the CTBT but not yet ratified it.  Among states in this position is the United States. As noted above, the U.S. did sign the CTBT in 1996, but when the treaty was presented to the U.S. Senate for its consent to ratification, the Senate in 1999 voted not to give that consent.  So the U.S. is in the position of having signed but not yet ratified the CTBT, because the Senate rejected the treaty.

An interesting legal question is whether the U.S. is currently in fact obligated under international law, pursuant to VCLT Article 18, not to act in a manner which would defeat the object and purpose of the treaty.  You might think the answer to this question is obvious in the affirmative – the Arms Control Association certainly seems to think so, as it expressed in this piece following the adoption of Resolution 2310.  But in fact the answer to that question is not at all simple or clear cut.

For starters, the U.S. is not a party to the Vienna Convention on the Law of Treaties. So it can’t be maintained that the U.S. is subject to this principle as a rule of treaty law. Then the question becomes whether the principles in VCLT Article 18 are also a part of customary international law. I honestly didn’t know the answer to this question, so I looked at academic commentary on the VCLT, and it appears far from clear that there is sufficient state practice and opinio juris to establish the Article 18 principles in customary law, independent of their codification in treaty law.  So that’s a significantly complicating aspect of the analysis.

Even if one could, arguendo, determine that the U.S. is subject to the principles in VCLT 18 as a matter of customary law, if you take those principles as they are iterated in the text of Article 18, there is still some considerable doubt as to whether the U.S. is currently legally obligated not to act in a way that defeats the object and purpose of the CTBT.

The issue here is that Article 18 provides that a signed but not ratified state does have such an obligation “until it shall have made its intention clear not to become a party to the treaty.” As I noted, President Clinton sent the CTBT to the Senate for its consent and the Senate in 1999 voted not to give its consent. Did this action manifest the intention of the United States not to become a party to the treaty? I think there’s a strong case to be made that it did.

Following the Senate’s rejection of the CTBT, the issue of the U.S. residual obligation, if any, pursuant to VCLT Article 18 has come up on a number of occasions, prompting contradictory statements from U.S. Secretaries of State.  For a discussion of these statements and their implications, I would refer readers to the below link for an analysis by Stephen Rademaker in testimony he gave to the Senate Foreign Relations Committee in September of this year.  In my 2011 book I was quite critical of Rademaker’s comments interpreting the NPT while he was in government.  But I actually think his analysis on pages 3-7 of this testimony of the international legal issues relative to U.S. obligation concerning the CTBT are pretty good.

On the whole, from a formalist perspective, I think it’s quite doubtful that the U.S. is in fact currently obligated as a matter of international law not to act in a manner which would defeat the object and purpose of the CTBT.  The Obama administration apparently has a different view, and wanted to express its view in the joint statement it issued along with the other NPT NWS. In that statement, the U.S. also recommitted to a unilateral moratorium on nuclear weapons testing.

In light of all this, the question of whether the U.S. is legally bound not to undermine the CTBT isn’t particularly material at the moment, as the U.S. under the current administration is politically committed not to do so. But the issue does come up once in a while, and it is useful to revisit the legal question.

rademaker-on-ctbt