Defending the FSA Against Russia — the Jus ad Bellum Perspective

It’s been widely reported over the past few days that Russia has been bombing the Free Syrian Army under the pretext of joining the fight against ISIS. That development spurred an interesting post at Lawfare by Bobby Chesney about whether Art. II of the Constitution — the Commander-in-Chief Clause — would permit the US to defend the FSA, which it has been equipping and training. As Bobby points out, rather skeptically I think, the USG seems to believe it would (internal block quote omitted):

[I]t is an interesting legal question, especially in light of recent testimony from Under Secretary of Defense for Policy Wormuth to the effect that Article II could be invoked to permit U.S. forces to defend DOD-trained Syrian forces in the event of an attack on them by Assad regime forces.  Wormuth’s position was repeated by an unnamed “senior administration official” a few days ago.

Given this position, is there any reason to think the answer would be different if we are talking instead about Russian forces attacking those same DOD-trained units?  I see no reason why that would be the case, though the policy stakes obviously are immensely different.  Next, is there anything different if instead we are talking about CIA-trained, rather than DOD-trained, Syrian forces.  Again, I can’t see why this would alter the analysis; under the apparent theory of the Obama administration, the government already possesses whatever legal authority would be needed to use force to prevent Russian jets from striking U.S.-sponsored Syrian units.

I have no doubt Bobby’s right — as I said on Twitter, he has forgotten more about Art. II than I ever knew. I just want to point out that invoking Art. II to defend the FSA against Russia would be more than a little perverse given the status of such an attack under international law — the jus ad bellum, in particular.

Let’s start with Russia. Although its attacks on the FSA might have violated the jus in bello — I certainly wouldn’t be surprised — they did not violate the UN Charter’s prohibition on the use of force with regard to Syria, because they were conducted with the Syrian government’s consent. Nor is there any plausible argument for viewing the Russian actions as an armed attack on the US — whatever the Art. II argument about the US’s “national interest” (see this skeptical Jack Goldsmith post), an attack on the FSA is not a use of force against the US’s “territorial integrity or political independence.”

What this means, of course, is that the US could not invoke self-defense under Art. 51 to justify using force against Russia to defend the FSA — say, by destroying a Russian bomber. Not only would such a use of force create an international armed conflict between the US and Russia, it would itself qualify as an armed attack under Art. 2(4), thereby permitting Russia to use force against the US in self-defense. Russia would simply be responding to an unlawful act of aggression by the US.

(To be sure, the same analysis would apply to any US use of force against Syria in defense of the FSA. But it would obviously be a much bigger deal for the US to commit an aggressive act against a major Western power — one that is also a permanent member of the Security Council.)

Again, I have no idea how these jus ad bellum considerations affect the Art. II analysis. Knowing the US, the fact that attacking Russia would qualify as an unlawful act of aggression might be irrelevant. The optics of using Art. II to justify such an attack would nevertheless be deeply troubling, to say the least.