The Absence of Practice Supporting the “Unwilling or Unable” Test
Regular readers of the blog know that one of my hobbyhorses is the “unwilling or unable” test for self-defense against non-state actors. As I have often pointed out, scholars seem much more enamored with the test than states. The newest (regrettable) case in point: my friend Claus Kress, who is one of the world’s best international-law scholars. Here is what he writes in an otherwise-excellent contribution to Just Security about the use of force against ISIL in Syria (emphasis mine):
It therefore follows not only from the right of self-defense’s general requirement of necessity, but primarily from the respect for the sovereignty of the territorial State that the right of self-defense in case of a non-State armed attack is of a subsidiary nature. It presupposes that the territorial State is either unwilling or unable to end the non-State armed attack – or, as it should be added for the sake of completeness, fails to exercise due diligence to that effect. State practice is remarkably consistent with these principles. As Professor Ashley Deeks has demonstrated in a formidable article, the legal claims to a right of collective self-defense in cases of non-State armed attacks have generally included the statement that the territorial State is unwilling or unable to deal with the non-State threat.
In terms of what the “unable or unwilling” test might look like if it represented customary international law, Deeks’s article is indeed excellent. But the article is anything but “formidable” in terms of state practice that supports the test. Indeed, the non-state actor section of the article spans all of two pages (pp. 501-03) — and cites precisely two states that officially endorse “unwilling or unable”: the United Kingdom and the United States. That’s it. And those are the same two states that Claus discusses in his post.
Simply put, there is simply no “consistent practice” that supports the “unwilling or unable” test, and scholars need to be careful not to put states in the “unwilling or unable” camp simply because they are willing to use armed force against a non-state actor. Deeks has been particularly prone to this kind of overinclusiveness, most recently arguing that Jordan, Bahrain, Qatar, the UAE, and Iraq support the “unwilling or unable” test because they have attacked ISIL in Syria — this despite the fact that all five states are members of the Arab League, which has specifically rejected the test in the context of Israel’s attacks on Hezbollah in Lebanon. (Actual opinio juris.)
I have the utmost respect for Claus, and I have no desire to pick on Deeks. But methodological rigor is particularly critical when it comes to doctrines like “unwilling or unable,” because its actual adoption by states would open the floodgates to the extraterritorial (ie, sovereignty-infringing) use of force against non-state actors. There may well come a time when the “unwilling or unable” test reflects customary international law, but that time is not now. Two states do not a customary rule make, however powerful those states may be. And we cannot simply ignore the states in the Global South, however inconvenient powerful states in the Global North may find their views.