Brian Egan, the new State Legal Adviser — and until recently the Legal Adviser to the National Security Council — just delivered this speech to the American Society of International Law. [UPDATE: The video is now available here and below.] As Egan notes, there is not much that is new or pathbreaking in it, yet I still strongly recommend reading [or listening to] it, because it is a very clear and useful summary — perhaps the best articulation — of the United States’s understanding of the international law basis for, and limitations on, its use of force against ISIL. Egan stressed that “the United States complies with the international law of armed conflict in our military campaign against ISIL, as we do in all armed conflicts” — with no hint of any exceptions. [UPDATE: In the Q&A, Egan referred to such LOAC compliance as a “lodestar,” and that the U.S. applies the LOAC “across the board.”] His speech also included many important explications of the U.S.’s understandings of how international law applies to the armed conflict with ISIL.

Jus ad bellum

Article 2(4) of the U.N. Charter provides that states “shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.”

According to Egan, the most common reason that the U.S.’s use of force overseas does not violate Article 2(4) is consent: “States generally rely on the consent of the relevant government in conducting operations against ISIL or other non-State actors even when they may also have a self-defense basis to use force against those non-State actors, and this consent often takes the form of a request for assistance from a government that is itself engaged in an armed conflict against the relevant group.”

In particular, “the United States’ actions in Iraq against ISIL have been premised on Iraq’s request for, and consent to, U.S. and coalition military action against ISIL on Iraq’s territory in order to help Iraq prosecute the armed conflict against the terrorist group.”

By contrast, when it comes to the use of force in Syria, the principal justification for U.S. operations is the collective self-defense of Iraq, which had already suffered armed attacks from ISIL. And this is true regardless of whether Syria is in some sense “responsible” for ISIL’s armed attacks. This is because, as Egan explains, “the inherent right of individual and collective self-defense recognized in the U.N. Charter” — which Article 51 preserves as an exception to the prohibition of Article 2(4) — “is not restricted to threats posed by States.” (Some academics question this conclusion; but, as far as I know, no states do so.) Egan notes that this has been the understanding of the right to self-defense “for at least the past two hundred years,” during which time “States have invoked the right of self-defense to justify taking action on the territory of another State against non-State actors.”

Egan stresses that the “armed attack” condition for the exercise of the Article 51 right of self-defense refers “not only . . . to armed attacks that have occurred, but also in response to imminent ones before they occur.” As I note at the end of this post, two or three aspects of this “imminence” notion are the most likely source of future debate about the U.S. views reflected in the Egan speech. On the other hand, this might be — thus far — merely a theoretical set of concerns, because it is not clear that the United States has actually ever relied upon the mere threat of imminent attacks (as opposed to threat of such attacks established by actual, completed attacks) as the basis for any Article 51 defense.

As Egan explained, the international law of self-defense requires that uses of force in self-defense, without host-state consent, are “necessary to address the threat giving rise to the right to use force in the first place. States therefore must consider whether unilateral actions in self-defense that would impinge on a territorial State’s sovereignty are necessary or whether it might be possible to secure the territorial State’s consent before using force on its territory against a nonState actor.”

It is in connection with the “necessity” requirement that the “unable or unwilling” test arises. As Egan correctly notes, the “unable or unwilling” inquiry is an important application of the necessity requirement. A state cannot use force against a nonstate actor without the consent of the host state unless “measures short of force have been exhausted or are inadequate to address the threat posed by the non-State actor emanating from the territory of another State.” If the host state were willing and able to address the threat, then this condition of the U.S.’s use of force would not be met.

With respect to Syria, in particular, Egan explained that the U.S.’s use of force in self-defense (including defense of Iraq) is necessary because Syria is “unable” to adequately deal with the threat from ISIL: “By September 2014, the Syrian government had lost effective control of much of eastern and northeastern Syria, with much of that territory under ISIL’s control.”

Jus in bello

Egan also addressed the international law constraints on how the U.S. can use force in the armed conflict. He specified that the customary laws of war require the U.S., even in a noninternational armed conflict, to strictly comply with the requirements of distinction, precaution, and proportionality, and the prohibitions against indiscriminate attacks, attacks using inherently indiscriminate weapons, attacks directed against specifically protected objects such as cultural property and hospitals, and acts or threats of violence the primary purpose of which is to spread terror among the civilian population.

Egan spoke specifically about how the U.S. decides whether a specific individual may be made the object of attack, either as a member of enemy forces or as a civilian directly participating in hostilities. The United States, said Egan, “look[s] to all available real-time and historical information,” including indicia of “certain operational activities, characteristics, and identifiers.” “For example, with respect to membership in an organized armed group, we may examine the extent to which the individual performs functions for the benefit of the group that are analogous to those traditionally performed by members of State militaries that are liable to attack; is carrying out or giving orders to others within the group to perform such functions; or has undertaken certain acts that reliably indicate meaningful integration into the group.” Egan “emphasize[s] a point that we have made previously, [that] it is not the case that all adult males in the vicinity of a target are deemed combatants.” [UPDATE: Charlie Savage raises questions about whether DoD applied a presumption of this sort — properly or not — in the “Operation Haymaker” operation in northeastern Afghanistan from 2012 to 2013.]

U.S. policy constraints beyond what the laws of war require

Toward the end of his speech, Egan further explained that “[i]n many cases, the United States imposes standards on its direct action operations that go beyond the requirements of the law of armed conflict.” For example, “although the United States is not a party to the 1977 Additional Protocol II to the 1949 Geneva Conventions and therefore not bound to comply with its provisions as a matter of treaty law, current U.S. practice is already consistent with the Protocol’s provisions.”

Most importantly, outside of designated “areas of active hostilities,” U.S. operations are further governed, over and above international law, by the President’s 2013 policy guidance (PPG), based upon the President’s belief “that implementing such heightened standards outside of hot battlefields is the right approach to using force to meet U.S. counterterrorism objectives and protect American lives consistent with our values.” The PPG “establishes measures that go beyond the law of armed conflict in order to minimize risks to civilians to the greatest extent possible. In particular, the PPG establishes a threshold of ‘near certainty’ that non-combatants will not be injured or killed. . . . In addition, with respect to lethal action, the PPG generally requires an assessment that capture of the targeted individual is not feasible at the time of the operation.” [The President, of course, has the authority not to apply the PPG in a given case, as long as the conduct is consistent with the laws of armed conflict.]

The PPG rules do not apply to what the Guidance itself identifies as “areas of active hostilities.” Egan stated that “[t]he Administration currently considers Afghanistan, Iraq, and Syria to be ‘areas of active hostilities'” in which the PPG does not apply. [UPDATE: In the Q&A, in response to a question from Charlie Savage about whether the Federally Administered Tribal Areas of Pakistan are also “areas of active hostilities” in which the PPG does not apply, Egan stated: “Sometimes others have referred to the Afghanistan/Pakistan border region as being part of what we talk about with respect to Afghanistan.”]

Actual and imminent threats of armed attack for purposes of Article 51

There are three passages in the Egan speech that might, I think, engender the most questions and pushback. All of them relate to the Article 51 “inherent right of individual or collective self-defence if an armed attack occurs.”

First, Egan states that “[w]hen considering whether an armed attack is imminent under the jus ad bellum for purposes of the initial use of force against a particular non-State actor, the United States analyzes a variety of factors,” including “the nature and immediacy of the threat; the probability of an attack; whether the anticipated attack is part of a concerted pattern of continuing armed activity; the likely scale of the attack and the injury, loss, or damage likely to result therefrom in the absence of mitigating action; and the likelihood that there will be other opportunities to undertake effective action in self-defense that may be expected to cause less serious collateral injury, loss, or damage. The absence of specific evidence of where an attack will take place or of the precise nature of an attack does not preclude a conclusion that an armed attack is imminent for purposes of the exercise of the right of self-defense, provided that there is a reasonable and objective basis for concluding that an armed attack is imminent.”

I imagine that this list of factors will be the most discussed and debated passage in the speech. [UPDATED: In my humble opinion, just as it is accurate to consider “unable or unwilling” as a function of the ad bellum requirement of necessity (see above), so, too, would it be more useful and accurate to think of “imminence” not as a distinct requirement, but as an application of the necessity requirement (which is the context in which it was discussed in the canonical Caroline case).]

It is noteworthy, however, that it is not clear the United States has ever acted in reliance upon these “imminence of future armed attack” factors. As far as I am aware, at least since the Cuban Missile Crisis, every time the U.S. has invoked self-defense as the justification for the use of force in a nonconsenting state, it has been after an actual armed attack, either against the U.S. itself (e.g., the attacks of September 11, 2001), or against an ally in whose defense we are acting (e.g., ISIL’s attacks on Iraq and France). That is to say, it’s not clear that the U.S. has ever had to invoke self-defense in a purely anticipatory setting.

Second, Egan remarked that although the U.S. “has not relied solely” on its own self-defense as an international law basis for taking action against ISIL in Syria — collective self-defense of Iraq has been a sufficient justification — the United States “maintains an individual right of self-defense against ISIL,” as suggested in its Article 51 notice to the United Nations. Because ISIL has not yet actually engaged in an armed attack against the United States, this assertion suggests that the U.S. believes that ISIL’s presence in Syria presents an “imminent” threat of an attack on the United States. This might or might not be correct; but, as far as I know, the government has not (yet) publicly offered any specific evidence — any assessment of the “factors” listed above — to support such an “imminent threat of attack on the U.S.” theory.

Finally, Egan stated that “[i]n the view of the United States, once a State has lawfully resorted to force in self-defense against a particular armed group following an actual or imminent armed attack by that group, it is not necessary as a matter of international law to reassess whether an armed attack is imminent prior to every subsequent action taken against that group, provided that hostilities have not ended.”

That statement might be true as a formal, technical matter, but the ad bellum requirements of necessity and proportionality would prohibit or limit continuation of the operations in the nonconsenting state if the threat of attack from the nonstate actor diminishes or disappears. (Egan’s speech does not suggest otherwise.) In other words, once the threat is removed, there would no longer be a need for continued nonconsensual use of force, and therefore the Article 2(4) prohibition would then kick in, even if the initial use of force was a legitimate act of self-defense.