International Law

“Unwilling or Unable” in the Legal Adviser’s ASIL Speech

By Douglas Cantwell
Tuesday, April 12, 2016, 3:46 PM

To paraphrase Mick Jagger—you can’t always get the international law argument you want, but sometimes, you get (some of) what you need. Recently, State Department Legal Adviser Brian Egan addressed the American Society of International Law (ASIL). Prior to Egan’s speech, I lamented , while writing about U.S. Special Forces in the fight against ISIS, that there had not been a full articulation by the Obama administration of its international law basis for intervening in Syria. Egan’s speech offered far more detail than previous iterations of the jus ad bellum argument. Importantly, it hinted at parameters for the “unwilling or unable” test. How the Obama administration interprets that controversial standard is crucial to understanding the U.S. position on the right to use force in self-defense against non-state actors.

Egan on “Unwilling or Unable”

The Legal Adviser’s address deserves praise for providing far more detail than previous articulations of the jus ad bellum argument for intervention in Syria. By comparison, in his 2015 speech to ASIL, then-General Counsel to the Department of Defense Stephen Preston devoted five sentences to the topic, referencing collective defense of Iraq and U.S. national self-defense and invoking “unwilling or unable,” all in general terms.

Egan devoted roughly a third of his speech to jus ad bellum. He gave the clearest picture to date of why the U.S. believes its actions in Syria do not violate the general prohibition on the use of force in Article 2(4) of the UN Charter. While this was a welcome and much-needed explanation, important parts of the argument remain opaque. A host of commentators (respectively, Ashley Deeks, Jack Goldsmith, Daniel Bethlehem, Goldsmith again, Fionnuala Ní Aoláin and Marty Lederman) have weighed-in on why Egan’s definition of “imminence” may seem familiar. But the commentary has largely overlooked what Egan said, both explicitly and by omission, about the contours of the “unwilling or unable” test.

As Rita Siemion and Heather Brandon note, Egan strongly endorsed “unwilling or unable.” He described it as a right of states to act in self-defense against a group operating out of a third-state, absent that state’s consent, when “there is a reasonable and objective basis for concluding that the territorial State is unwilling or unable to effectively confront the non-State actor...” Applied to Syria, he stated:

For example, in the case of ISIL in Syria, as indicated in our Article 51 letter, we could act in self-defense without Syrian consent because we had determined that the Syrian regime was unable or unwilling to prevent the use of its territory for armed attacks by ISIL. 

As Egan acknowledged, this is not a new argument. The U.S. invoked “unwilling or unable” when it began intervening in Syria, in Ambassador Power’s letter to the UN.  But Egan’s use of the past tense is important. He said earlier:

[O]nce 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.

The point of reference for whether the Assad regime was “unwilling or unable” was September 2014, when Ambassador Power submitted an Article 51 letter to the UN. Egan seemed to suggest a state has no duty to reassess whether the host state is still “unwilling or unable” as long as the non-state group continues to engage in hostilities that threaten the intervening state. Practically, this suggests a host state that is deemed to be “unwilling or unable” cannot regain its right to sovereign noninterference if it later develops the ability or willingness to address the non-state actor (including by phoning a friend for help). Egan seemed to say that even by addressing the threat itself, the host state cannot moot, ex post facto, the claim of the intervening state.

One qualification is that the intervening state may need to show that continued intervention is “necessary.” But this provides little assurance against abuse. Given Egan’s offered definition of imminence, it is not clear when an intervening state would find it unnecessary to continue operations against a group, absent the group’s total destruction.  For example, it is difficult to imagine the U.S. suddenly ending cross-border strikes against ISIS on account of recent battlefield successes by Syrian government forces.

Nor is it clear how this necessity calculation would apply to armed groups who are hard to separate from their civilian counterparts in self-governing autonomous regions. Even those who applaud continued U.S. action against ISIS in Syria should be troubled that, in Egan’s formulation, the necessity of continued intervention would be determined unilaterally by the intervening state, without any hard and fast criteria, and might continue in perpetuity as long as the group posed some future harm. Consider how Turkey might apply this argument to justify strikes against Kurdish fighters in Syria or Iraq, based on claims to self-defense against the PKK. Frankly, consider how this argument might apply against any non-state armed group not named or modeled after al-Qaeda or ISIS.

Unable = Loss of Effective Control?

The danger of states unilaterally determining their right to intervene in host states should give the international community pause. At a minimum, the risk of states abusing a nebulous standard calls for a precise definition of “unwilling or unable.” A frequent critique of “unwilling or unable” is that, despite a history of state practice, there is little opinio juris, thus it cannot be said to exist de lege lata as customary international law.

Unfortunately, Egan did not give a full definition of “unwilling or unable.” Like pornography in Justice Potter Stewart’s famous quip, are we expected to trust that states will know it when they see it? Egan provided a bit more than that, both explicitly and by omission. The bombshell in Egan’s speech is the emphasis he placed on effective control in defining “unable.” He said:

With respect to the “unable” prong of the standard, inability perhaps can be demonstrated most plainly, for example, where a State has lost or abandoned effective control over the portion of its territory from which the non-State actor is operating.  This is the case with respect to the situation in Syria.  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.

To be fair, the statement is carefully worded and contains qualifiers, suggesting effective control by itself isn’t dispositive and may not be the only relevant factor. However, it does suggest that loss of effective control was determinative in the case of Syria.

Egan’s failure to offer more detail or additional factors is particularly puzzling in the context of his speech. As Ashley Deeks noted, states increasingly resort to multi-part tests (MPTs) when justifying uses of force that don’t fall within the strict confines of the UN Charter. (Deeks herself formulated a MPT for “unwilling or unable,” which deserves consideration). To many, Egan’s speech seemed to endorse in its entirety another MPT, 16 factors that Daniel Bethlehem presented in a 2012 article in the American Journal of International Law. Upon closer inspection, as Simeion and Brandon pointed out, Egan only endorsed one of those factors, Principle No. 8, for determining whether an armed attack is imminent. Egan listed each of the imminence factors included in Principle No. 8 in his remarks. 

Principles 9 through 13 of the ‘Bethlehem Factors’ address host state consent, unwillingness, and inability. Factor 12 discusses inability and “reluctant hosts,” allowing for intervention when, “there is a reasonable and objective basis for concluding that the third state is unable to effectively restrain the armed activities of the nonstate actor.” Effective control does not appear explicitly in Principle No. 12, although it could be read-in as part of the “reasonable and objective basis” or as “effective restraint.” However, expressio unius est exclusio alterius. Egan’s failure to acknowledge Principle No. 12 of the Bethlehem Factors suggests the U.S. government does not endorse Bethlehem’s formulation of “unable.”

Unanswered Questions Surrounding Effective Control

Egan’s short reference to effective control raises more questions than it answers. For how long must a government lose effective control before its territory can be subject to intervention on self-defense grounds? Over how large of an area must effective control be lost? Does loss of effective control of one part of a state allow transit through other parts still controlled by the government, if necessary? Does the group the intervening state is defending against have to exercise effective control or, is it sufficient that the internationally recognized government has lost it, such as in the case of competing factions vying for control? Does it matter whether a non-state armed group declares its intention to carve out a separate state, like ISIS has?

Most importantly, who decides when a state has lost effective control over a part of its territory? In the case of ISIS, it was, somewhat surprisingly, UN Secretary General Ban Ki-Moon. When airstrikes began in September 2014, he said:

I am aware that today’s strikes were not carried out at the direct request of the Syrian Government, but I note that the Government was informed beforehand.  I also note that the strikes took place in areas no longer under the effective control of that Government.   I think it is undeniable – and the subject of broad international consensus – that these extremist groups pose an immediate threat to international peace and security.

Perhaps this is why Egan was so quick to offer loss of effective control as a guidepost. But why only mention effective control? Why not instead highlight Ban’s invocation that a “broad consensus” considered the chaos in Syria an “immediate threat to international peace and security”? Will the U.S. consider the Secretary General’s implicit blessing to be a key component of future interventions under “unwilling or unable”? Would a determination of loss of effective control by the Security Council be sufficient, without invoking Chapter VII?  Would determinations of loss of effective control by regional groups like the African Union or Arab League or EU add a gloss of legitimacy? Perhaps the UN General Assembly will join the business of pronouncing on loss of effective control under Uniting for Peace.  Without more detail, commentators are left guessing as to the U.S.’s position. As is, it appears that intervening states may determine unilaterally that: i) a host state has lost effective control; and ii) that loss justifies a use of force under “unable.” 

The Assad Regime Was Not “Unwilling”

Next, the omission: much is said from what was unsaid. Egan explicitly invoked the unable prong of the test. Nowhere else in his speech did he similarly define “unwilling.” Again, expression unis. Egan’s failure to define “unwilling” implies the U.S. views “unwilling or unable” as a strictly disjunctive test. The two criteria must be identified and analyzed independently. This gives two alternate bases for determining if a state is unwilling or unable, which might give intervening states more latitude to determine whether the standard has been met.  

More importantly, Egan’s omission suggests the Assad regime was willing to tackle the threat posed by ISIS in September 2014 (or at least that it was not “unwilling”). Before airstrikes began, there were suggestions that the Syrian government was not really willing to engage ISIS, preferring to use the threat of ISIS to deflect attention away from its own abuses and allow the opposition to bear the brunt of ISIS’s destructive capabilities. Inferring from Egan’s omission that the Assad regime was not “unwilling,” the minimal steps the regime had taken to counter ISIS before September 2014 may be enough to stave off a finding of “unwilling,” a relatively low bar. It may also mean that the Assad regime’s offers to “coordinate” with the U.S., which were quickly rebuffed, satisfied the minimum threshold of willingness.


Egan’s brief invocation of effective control provides an opening for commentators to begin to define the contours of “unwilling or unable.” Effective control is well defined in the law of occupation and is mentioned in the U.S. Army Field Manual. There is substantial case law on effective control by international bodies, including the U.S. Military Tribunal in Nuremberg in Von List, the ICJ in DRC v. Uganda (2005), and the ECtHR in al-Skeini. Perhaps jurisprudence can provide grist for the mill.

But placing too much weight on effective control is not without peril. For example, if effective control were the only or the primary determinant, Russia would be within its rights to intervene against ISIS in Iraq. After all, the Iraqi government has lost effective control of part of its territory—including Mosul, a city of 2 million people—to ISIS, which has threatened attacks on Russia.

Perhaps vaguely referencing effective control was as far as Egan was authorized to go, leaving future flexibility as the unsettled law of “unwilling or unable” develops. Perhaps, acknowledging his speaking time was limited, he wanted to address concerns like those Charlie Savage expressed about the PPG. While Egan’s speech was a start, the Obama administration should continue to clarify—publicly and in detail—its argument for intervention in Syria. Failing to give any objective definition for “unwilling” and a vague reference to loss of effective control for “unable” leave the already contentious standard open to abuse. Without better-defined parameters, “unwilling or unable” may become an international law Rorschach test, open to infinite interpretation based on the beholder.