Last week, Elena Chachko and Ashley Deeks posted a helpful resource at Lawfare: a compilation of states’ pronouncements on the use of defensive force against nonstate actors. Readers no doubt know that there is an ongoing debate about whether and, if so, under what circumstances a state may use force in self-defense against nonstate actors that operate from another state. The Lawfare post asserts that ten states have expressly endorsed the unable-or-unwilling standard, under which defensive force would be permissible if the “host” state is unable or unwilling to contain the violence. The post then characterizes three states as having implicitly endorsed the unable-or-unwilling standard; eighteen as ambiguous about that standard; and four as expressly objecting to it.
We disagree with some of those characterizations. A few of the “express” endorsements seem to us to be less definitive than Chachko and Deeks claim. Moreover, we don’t think the “implicit” or “ambiguous” endorsements are endorsements at all. In these cases, the acting states seem not to support the unable-or-unwilling standard but rather to articulate a narrower standard -one that is limited either to the host state’s affirmative support for the nonstate group or to that state’s loss of control over portions of its territory. (For a discussion of the various standards that might be in play, see this article.)
We want to focus here on a more interesting phenomenon: in the current fight against the Islamic State, six states have invoked in their reports to the Security Council a combination of Resolution 2249 and Article 51 to justify their use of force in Syria. (The six states are Belgium, Denmark, Germany, the Netherlands, Norway, and the United Kingdom.) Resolution 2249 was adopted in November 2015. It “determin[ed]” that the Islamic State “constitutes a global and unprecedented threat to international peace and security” and “not[ed] the letters . . . from the Iraqi authorities which state that Da’esh has established a safe haven outside Iraq’s borders that is a direct threat to the security of the Iraqi people and territory.” The Council also:
“call[ed] upon Member States that have the capacity to do so to take all necessary measures, in compliance with international law, in particular with the United Nations Charter, . . . to prevent and suppress terrorist acts. . . .”
This Resolution nowhere authorized the use of force. And even if it did, it would be unnecessary if Article 51 itself provided a basis for using force in Syria. The point of Article 51 is to permit unilateral force – that is, force without any Council action – in “true” cases of self-defense. As such, the Article 51 reports that reference 2249 are, at the very least, odd.
What might explain them? We think the six states are seeking to establish a limiting principle on the potentially expansive unwilling-or-unable claims that the United States and some other states have circulated. In their Article 51 reports, the six states rely on the Council’s recognition of two elements: (1) that the Islamic State poses an unprecedented threat to international peace and security, and (2) that this nonstate group is operating from one state to attack another. The six states are thus using Resolution 2249 to establish a legal fact – that the preconditions for defensive force have in this case been met. The clear implication is that the preconditions are not for the acting state alone to determine. In other words, the acting state may not use defensive force simply because it itself has decided that the host is unable or unwilling to contain an (actual or prospective) attack. That decision might instead be for the Council to make.
In a recent article, we argued the regime on the use of force is best understood as a site of ongoing contestation and compromise between two visions of the legal order: one that prioritizes the regulation of the use of force through collective decisionmaking in international institutions and a second in which states act in a disorganized fashion to tolerate greater unilateral force. We surmised that, although the regime’s most active participants propound two very different normative visions for the regulation of the use of force, these actors generally have an interest in reconciling their conflicts. As we explained, direct confrontations between their positions “call into question the entire premise of the regime: that the use of force in international affairs is and should be meaningfully regulated.” No part of the use of force regime is more contested than the nonconsensual and extraterritorial use of force against nonstate actors. In these recent letters, we see a move to try to “rebalance” Article 51 by establishing a role for the Council or otherwise raising the bar on the use of defensive force. This move at once recognizes the contemporary threat of nonstate actors (and the possible need to use force against them) and preserves the limiting function that collective decisionmaking is supposed to serve.