In the last couple weeks, the White House has been hard-pressed to make a good-faith legal argument on why a unilateral U.S. strike would not run afoul of the UN Charter’s prohibition on the use of force. While the White House continues to claim that any such strike would be legal, it has yet to flesh out in detail the basis for such a claim. Meanwhile, a clear consensus has developed in the legal community that the best the White House Counsel can offer President Obama is a ‘legitimate but illegal’ argument styled in the manner of the NATO intervention in Kosovo. The ‘unique factor’ approach suggested by some in the Obama administration has received little but ridicule in the legal blogosphere, divorced as it is from both the text of the UN Charter and past precedent.
With a Russia-led proposal on the table, however, a U.S. strike is beginning to look less and less likely. The proposal – whereby Syria would ship its CW stockpile to a third-party state as to assure the international community as to its future disuse – has received considerable attention in the past 24 hours, including a statement of interest by the White House itself. There has also been a flurry of activity over at the United Nations, where France earlier tabled a resolution effectively mirroring the proposal (though a Council meeting scheduled this afternoon was cancelled over apparent disagreement on whether such resolution should properly invoke the Council’s Chapter VII enforcement powers).
Meanwhile, the White House has considered itself vindicated by the turn of events. During yesterday’s press conference, Deputy National Security Advisor Tony Blinken claimed that it was only the U.S. threat to use force that had made Syria agreeable to such a proposal. Without the shadow of U.S. intervention in the foreground, Blinken argued, no such proposal would have been launched.
If true, however, the U.S. might be running afoul of the law once again. International law does not take kindly to unlawful threats or uses of force, and treaty law is no exception to this rule.
Under the Vienna Convention on the Law of Treaties (VCLT) Article 52, “a treaty is void if its conclusion has been procured by the threat or use of force in violation of the principles of international law embodied in the Charter of the United Nations.”
There are two basic elements to VCLT Article 52: (1) a treaty must have been procured by a threat or use of force; and (2) the threat or use of force must be unlawful (i.e., it must violate UN Charter Article 2(4)). The latter element is most likely present in this case. The best idea we have as to what constitutes an unlawful threat of force is found in the ICJ’s Advisory Opinion in the Nuclear Weapons Cases. There, the ICJ held that a threat to use force is unlawful when the force threatened would itself be unlawful under the UN Charter. That is, if engaging in a unilateral strike on Syria would be an unlawful use of force, then the threat to use such force would likewise run afoul of UN Charter Article 2(4). In this case, as noted, almost all legal scholars agree that a unilateral U.S. strike on Syria would be illegal absent either a UNSC resolution or a legitimate self-defense claim. Thus, the second element of VCLT Article 52 is, in all probability, met in this case.
The more difficult argument is that the potential agreement between Syria and other States was procured by the U.S.’s threat to use force – that is, that the unlawful threat of force is the reason for Syria’s consent to the proposed agreement. The U.S. is claiming to be responsible for Syria’s willingness to deal, but that claim does not establish causality as a matter of fact. Moreover, the proposal originated with Syria and its allies, Russia and Iran – not from the threatening party, the U.S. These are all factors to consider when making the fact-intensive effort to determine whether or not any agreement between the parties runs afoul of VCLT Article 52’s prohibition on coercive diplomacy involving threats or uses of force.
In short, the U.S. should stop claiming to be responsible for producing a negotiated outcome because, to the extent that it is, that only works to make the agreement void under the relevant legal framework. Not a positive outcome for anybody.