Guest Post: Pesky Questions of International Law: What’s the basis for air strikes in Syria?

by Jennifer Trahan

[Jennifer Trahan is an Associate Clinical Professor of Global Affairs at NYU-SPS.]

President Obama’s speech on September 10th raised many legal issues, including, whether there needs to be added Congressional authorization for the use of force, or one can utilize the pre-existing Authorization for the Use of Military Force (“AUMF”) that Congress granted after 9/11 (see Deborah Pearlstein’s post and Peter Spiro’s).  But his speech also raised profound questions at a second level – that of public international law (touched upon by Kevin Jon Heller).

This may not seize the attention of the American public, but surely coalition partners would ask these questions:  what was Obama’s basis for the legality of air strikes in Syria?

It is somewhat troubling that President Obama took the step of supporting air strikes in Syria, without articulating any clear legal foundation at the international level.  Just to be clear, the issue of air strikes in Iraq against the Islamic State in Iraq and Syria (“ISIS”) does not raise similar questions, as Iraq had earlier consented to the use of force.

There are a number of possible legal rationales for air strikes in Syria, but the U.S. needs to make the case under one of these grounds.  Such a legal foundation was not well-articulated in President Obama’s speech. 

Consent of the Assad regime

Consent of the Assad regime would legitimize air strikes in Syria against ISIS.  Assad seems willing to grant such consent (at least according to one New York Times article), but seems to request coordination with the U.S., something the U.S. seems to presently rule out.
Security Council approval

Alternatively, the UN Security Council could authorize air strikes under its Chapter VII powers.  This is not as crazy as it sounds.  Previously, Russia was in a position to veto any UNSC voting that would have impacted negatively on the Assad regime.  However, because the Assad regime could benefit from air strikes against ISIS, Russia might not veto a UNSC resolution authorizing air strikes against ISIS in Syria.  The possibility of such a resolution should be explored.

Self-defense of the Iraqi people

If air strikes are viewed as collective self-defence of Iraq, and if ISIS poses a threat of trans-border attacks into Iraq, potentially, military action could be aimed at ISIS to prevent such trans-border attacks.  Such a legal foundation would not be a carte blanche for air strikes against ISIS in Syria, but would be grounded in preventing trans-border attacks or degrading ISIS’s capability to launch them.

Humanitarian intervention

ISIS is implicated in large scale atrocity crimes to date.  It might be possible to make an argument supporting intervention on grounds of humanitarian intervention, although President Obama did not appear to do so in his speech.  This is probably for good reason.  While NATO utilized such a doctrine in its 1999 Kosovo intervention, there is growing scepticism whether it can be used without Security Council authorization – as would be required for forceful intervention under the doctrine of the “responsibility to protect.”

Pre-emptive self-defense

To the extent that President Obama articulated any justification at the international law level, he seems to have chosen (in this author’s view) weaker arguments.  By arguing that ISIS is a “terrorist threat” and later suggestions from the White House that use of force could be covered by the post-9/11 AUMF, President Obama seems to argue either for pre-emption (attack ISIS before they attack the US) and/or that military force is part of the “global war against terror” that started post-9/11.  (The Obama administration usually frames it more narrowly as a war against “Al Qaeda and associated entities.”)

As to pre-emptive self-defense, this is a Bush Administration doctrine that has generally been discredited by many legal scholars.  Vague invocations of a “threat” to U.S. interests are not sufficient grounds to go to war.  President Obama doesn’t argue that the U.S. has suffered an “armed attack” from ISIS as would be needed to invoke self-defense.  Nor does he make the case of an “imminent” threat of an armed attack, the legal basis for utilizing anticipatory self-defense.

Part of a global war

While rhetoric of fighting a terrorist group or group once affiliated with Al Qaeda probably has appeal to the American public (particularly with Obama’s speech close to the 9/11 anniversary), there is widespread international scepticism about whether there is such a thing as a “global war,” and, even if there is, who is an appropriate target.  Even if one sees ISIS as a one-time “affiliate” of Al Qaeda (slight complication that it is no longer affiliated), many countries have remained sceptical of endorsing the global war framework.  While there was widespread support for the US post 9/11 as it started its military intervention in Afghanistan, that support eroded as the US response and all that the “global war” encompassed grew broader and broader.

The need to show international legal foundation

Thus, while it is not impossible that air strikes in Syria could be justified under international law, the Administration still needs to demonstrate a solid legal foundation for them.  Maybe the American public and members of Congress will not demand these answers (although they should), potential coalition partners most likely will.  Building a robust coalition, including Arab states, will be a key indicator of the acceptability of American action; not only should the US not bear the cost of going it alone, the ability to build a broad coalition (including on the issue of air strikes in Syria) will be an important indicator of legitimacy.

27 Responses

  1. Have you read the latest “manifesto” of ISIS? They claim the West are crusaders and they plan on a “final death blow” to the cross, rome, the United States, the europeans, the jews, the saudis, the “evil shias” and various other “enemies”. I think most Americans would agree that these nut jobs need to be sent away – permanently. This is a time for action.

  2. As noted in Opinio Juris in several posts, it is relatively easy — collective self-defense with the consent of the Iraqi government under UN article 51. Under the Const., the President has authority to use military force in self and collective self-defense, in accordance with UN arts. 42 and 48, or in accordance with UN art. 52 (“regional action”) under Article II, Section 3 of the Const. —
    Yes, a threat or “imminent threat” (which is not yet a threat) will not trigger UN 51 for U.S. self-defense — preemptive self-defense as such would be unlawful and unconstitutional.

  3. I ultimately do agree with Jordan that a theory of collective self-defense of Iraq is probably the strongest theory that the U.S. has for bombing of ISIS within Syria. It still is not necessarily a carte blanche, but has to be a proportionate response to the armed attack upon Iraq.
    Apparently, however, there is also another group that that the US has targeted within Syria (an Al Qaeda affiliate). If that group has not attacked Iraq, it cannot be brought under the same legal framework.
    Anticipatory self-defense would require an imminent threat (and that may be the theory as to the other group being targeted); pre-emptive self-defense is what I see as discredited (suggesting the permissibility of a strike before the threat is imminent).


    Says that US “informed” Syria in advance of its plans. Isn’t there a precedent for this in which we used to send Pakistan faxes announcing that we would be carrying out drone strikes and taking silence to be consent?

  5. Jennifer: Yes, proportionality is part of the inquiry, but the continued armed attacks by ISIS are massive. I don’t see a problem regarding proportionality.
    With respect to Khorasan, the al Qaeda affiliate, both UN 51 and the AUMF would support self-defense strikes by the U.S. on a group that has engaged in continued armed attacks. Thus, no need to address claims of anticipatory self-defense.
    Also, an “imminent threat” is not even a threat. It is at the very least a troubling phrase and sounds like the old discredited Bush doctrine. Perhaps you have in mind an imminent attack or a real threat of an imminent armed attack.
    And today Israel engaged a Syrian aircraft within Israeli airspace — another example of claims to engaged in permissible self-defense.
    Much for academia and our students to write about.

  6. EMF: that’s an interesting question, but a special consent is not required. Syria, as every member of the UN, has consented in advance to lawful measures of self and collective self-defense under the U.N. Charter, as members of the U.N. In any event, I do not suspect that most would accept that a notification and silence constitute a special consent.

  7. Jordan – as to most locations where the US has conducted air strikes against al Qaeda affiliated entities, there was also consent of the country. That provides an unquestioned legal basis. As to strikes where there is no such consent, that is on a less firm foundation — one that seems to be accepted within the U.S., but one that at least European partners appear to continue to question. It is potentially defensible, but much dicier than where there is consent of the country at issue. And, yes, I agree with you that silence by Syria is not consent.

  8. I think the administration proceeded without articulating an international legal theory generally supporting these attacks because it knew that it might assert different legal bases for different attacks. As this post and its comments show, the lawfulness of a use of force is contextual. The administration may rightfully claim collective self-defense as to one attack and self-defense as to another, as Jordan argues.

    Of course, all of this relates only to questions of jus ad bellum, meaning the resort to armed force. It does not address the legality of the nature of the force used. This post tends to collapse the distinction. If collective self-defense is the theory asserted, the attacks are clearly part of an armed conflict between ISIL and Iraq and regulated by international humanitarian law. If individual self-defense is advanced, one must offer an “associated force” argument for the al-Qaeda element or establish the existence of an independent non-international armed conflict with that group (Jordan’s theory of self-defense against non-state actors and DPAA notwithstanding). Otherwise, many would say international human rights law requires the use of law enforcement measures. Consent tells us absolutely nothing about the legality of a use of force.

    If anyone is interested, I have a new draft chapter up at SSRN that offers a different approach to these issues in the context of transnational counter-terrorism operations unrelated to an extant armed conflict. Comments are welcome (but needed SOON!)

    Best to all…

  9. John,
    Yes, you are right – there clearly are different legal theories going on. I still do think it would be helpful if the US would clearly articulate its theory for air strikes against ISIS (for which the legal foundation seems fairly defensible).

    But I disagree that “consent tells us nothing.” Consent is a KEY ingrediant to legality at the jus ad bellum level. But you are right that there are two legal frameworks additionally at issue — the IHL framework and the human rights framework. If there is consent, and the situation is within the IHL framework, then the consent is a key ingredient making use of force lawful. If the situation is not in an armed conflict framework (but a human rights framework), then consent does not make the use of force appropriate.

  10. Jennifer, I should have clarified again in that paragraph that while consent tells us nothing about the legality of the USE of force, it does support the RESORT to force. I try not to use those terms interchangeably but realize it can be confusing.

  11. John: look forward to viewing your latest.
    To clarify my view regarding the nature of the armed conflict with ISIS, I consider ISIS to meet the traditional criteria for an “insurgent” status but do not know of any state that has recognized ISIS as a “belligerent” (or nation or state). However, when the U.S. uses its armed forces in an armed conflict it should be recognized as being an IAC (for pow status, combatant immunity). And I am one who does not agree that the U.S. can be in an armed conflict with al Qaeda as such, but that the self-defense paradigm applies.
    John: I am not sure what you mean by consent tells us absolutely nothing, but I would certainly agree that consent is not required under the law of self and collective self-defense (with respect to which Jennifer sets out a caution).

  12. President Obama’s letter to Congress mentions his authority as commander in chief. His legal team is far behind us. His most important authority in the case of strikes against ISIS is under the U.S. Const., art. II, sec. 3 (his duty, and concomitant authority, faithfully to execute the “Laws,” which include international law, in this case, the law of collective self-defense).

  13. In the U.S. letter to the Secretary-General (dated today, for circulation to the UN Security Council), the U.S. is lumping together air strikes against ISIL/ISIS and those against the Khorasan Group. It references Iraq’s request to the US to lead strikes against ISIL, and the need to protect Iraqi citizens. This seems to fall squarely within article 51 self-defense.

    The part where I think we would have more disagreement (for a number of the reasons already mentioned above) is where the letter references strikes against the Khorasan Group, which the letter states is based on “threats that they pose to the United States and our partners and allies.”

  14. The hearsay in the NYT piece fits well with Iraqi self-defense against ISIS and consent re: U.S. collective self-defense — both in Iraq and Syria.
    Perhaps “they” are “reading” Opinio Juris?

  15. Re: the consent issue and the NYT piece, allegedly using remarks by Goldsmith & Goodman, it seems to miss the point that general consent has already been given in advance when states agree to ratify or accede to the U.N. Charter. Further, there may be a number of writers who would require Syria to provide a new, special consent, but are they actually within the minority? see (initial draft that has been expanded), what is now footnote 20, citing Dinstein, Deeks, me, Schmitt, Alston, NYC Bar Report.

  16. Jordan,

    It is a bit ironic, isn’t it, that many who would argue for humanitarian intervention to protect the human rights of a foreign population against (or in some cases, in spite of) its own government would not also allow a right to intervene in the territory of another state to protect the intervening state’s own nationals and their human rights from a reasonably certain, future attack.

  17. perhaps, but one must pay attention to the text and subsequent opinion juris

  18. DJ, while this might be “a time for action,” the Obama Administration should still have a solid legal justification for military action in Syria. From a moral/policy perspective, maybe the US *should* intervene. But from a doctrinal/legal perspective, it’s not entirely clear whether the US *can*.

  19. Eric,
    Just to clarify my position. I think the collective self-defense argument as to attacking ISIS in Syria is well-founded. The more complicated issues pertain to the Khorasan Group, where a different argument is at issue — whether the US can respond to a threat. This is a less clear proposition, and depends on one’s views on anticipatory/pre-emptive self-defense, and to some extent, the whole GWOT theory. Interestingly, it seems that Assad is not objecting to either intervention — so he is not asserting any sovereignty violation.

  20. New posting at JURIST is available here:

  21. the UK legal claim for UK joining in Iraq is in a click-on in a new posting over at EJIL Talk — which will be background for a UK debate in Parliament tomorrow.

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