As a number of my colleagues have been debating the lawfulness of the United States striking a Syrian airbase with 59 Tomahawk missiles in response to a purported chemical weapons attack by the Assad regime, I have asked similar questions but also focused on whether the Trump Administration may have been less concerned with international law than what the Administration views as America’s moral obligations.  Yet I remain surprised by how little attention has been paid in public debate to international criminal standards for aggression – particularly in light of recent comments by Vladimir Putin.

If I am correct that this operation may have been conducted based more on a sense of moral obligations than legal responsibility and that President Trump may have been willing to order this action without international legal justification to do so, then Vladimir Putin’s assertion that this operation constituted an act of aggression is particularly significant.  Without international legal justification to act – no matter how benevolent the motives – the strikes may be viewed by some as the crime of aggression.  And it is worth noting that Putin’s accusation came just a few days before members of Congress introduced a bipartisan bill that would “require a report on, and … authorize technical assistance for, accountability for war crimes, crimes against humanity, and genocide in Syria ….”

There are good reasons for Congress to take an interest in seeing that the perpetrators of war crimes are brought to justice.  There are also reasons to be concerned about how others might view the United States’ own actions.

The U.S. Government should know this reality because its own history is caught up in it.

In both the International Tribunal at Nuremberg and a separate U.S. Tribunal conducted after the conclusion of World War II, crimes of aggression were assessed to be war crimes based upon customary international law as it existed prior to World War II.  Specifically, the tribunals deemed the actions of “planning, preparation, initiation or waging a war of aggression, or a war in violation of international treaties, agreements or assurances, or participation in a common plan or conspiracy for the accomplishment of any of the foregoing” to be “crimes against peace.”  Moreover, the Charter of the Nuremberg Tribunal went so far as to state that “a war of aggression … is the supreme international crime differing only from other war crimes in that it contains within itself the accumulated evil of the whole.”

But, even if the Tomahawk strike might be viewed as an act of aggression, are all forms of aggression war crimes?  The Nuremberg Judgment indicated that a distinction existed at least for the purposes of those proceedings at that time in history, finding guilt for those who were found responsible for the “aggressive war” but not for persons participating in an “aggressive act.”  In the present context, some might argue similarly that limited-in-scale targeted strikes do not, in and of themselves, constitute wars of aggression, war crimes or crimes of aggression.  Such an argument might emphasize the limited scale and duration of these strikes (and perhaps that framing might be viewed with more leniency based on the moral undertones that I discussed previously).

Such an argument, however, would not relieve government officials of the obligation to refrain from the “planning, preparation, initiation or waging … a war in violation of international treaties, agreements or assurances” – those broader prohibitions that fell within the meaning of “crimes against peace” at Nuremberg and that have criminal liability implications in this context.  Additionally, while the proceedings at Nuremberg did not have the UN Charter as a reference point for assessing whether international treaties had been violated back then, today international lawyers most certainly do.

Another meaningful contemporary consideration is that many international lawyers today view aggression more appropriately characterized not as a war crime, but as a violation of international law with criminal liability or what many simply refer to as an “international crime.”  But exactly why and where these lines are drawn is less than clear.

The Rome Statute of the International Criminal Court and UN General Assembly Resolution 3314 are relevant sources for consideration.

Rome Statute (with amendment):  “crime of aggression” means “any act of aggression, which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations”

UN General Assembly Resolution 3314:  aggression is “the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State or in any other manner inconsistent with the Charter of the United Nations”

While the U.S. Government might not feel bound by the Rome Statute (or its amended form) or Resolution 3314 except to the extent that they reflect customary international law, it is worth considering whether one or both of these texts does accurately describe customary international law as it pertains to crimes of aggression.  It would not be unreasonable to conclude that at least the Rome Statute’s amendment is accurate in its description of certain acts of aggression as international crimes.

Of significance, however, the Rome Statute seems to acknowledge that not all acts of aggression would rise to the level of constituting crimes of aggression.  In fact, Claus Kress, a leading scholar on the Kampala Review Conference, reports that the U.S. Government proposed an exception to the crime of aggression for humanitarian interventions in 2010.  Kress’s analysis also suggests that the use of force for humanitarian intervention purposes may not rise to the level of a “manifest violation of the Charter of the United Nations.” To the extent that the Rome Statute might reflect customary international law, this is an important conclusion.

It does seem clear that the Rome Statute established a higher threshold than did Resolution 3314.  Nevertheless, it is at least worth pointing out some of Resolution 3314’s additional text in the context of the Tomahawk strike into Syria.  Most significantly, Resolution 3314 explains that aggression includes, among other things, “[b]ombardment by the armed forces of a State against the territory of another State or the use of any weapons by a State against the territory of another State.”

Of course, one would expect that, prior to undertaking the operation, U.S. Government lawyers would have carefully deliberated over the extent to which U.S. domestic and international law supported these strikes and, under the circumstances, whether there might be cause for concern over potential claims that the strikes constituted acts of aggression.  (Note that President Obama, while choosing to seek Congressional authorization prior to using force under similar circumstances, is on record as having concluded in August 2013 that he too felt justified to “take military action against Syrian regime targets” in response to Assad’s use of chemical weapons. )  It may be that these strikes, while significant in their destructive force, were deemed to have been of sufficiently short duration and for such limited, (arguably) benevolent purposes that the concept of aggression seemed misplaced.  Or maybe the Trump Administration found the ICC’s lack of jurisdiction over those U.S. persons who approved or conducted the strikes to be persuasive.

Whatever the legal analysis ultimately was and whatever the final motivation behind the decision proved to be, it is possible that the sense of morality that was attached to these responsive actions will cause U.S. Government officials to get the benefit of the doubt.  Perhaps the international community will view this particular use of force as a necessary measure to deter future chemical weapons strikes by the Assad regime – even if the strikes do not appear to comport with international law.

For now, these complications, and those that naturally attach to war, reinforce another point that I made previously.  The choice to use force should not be taken lightly.  And it is always worth remembering that benevolence is judged through the eye of the beholder.  One can never quite tell how broadly the ICC might interpret (or seek to extend) its own jurisdiction or even how the future of the Syrian conflict might someday weigh on how these strikes are ultimately judged. Those kinds of questions will loom large not only for the United States but also for our foreign partners who will need to decide whether they can support us in such actions.


Image: Russia’s Deputy UN Ambassador Vladimir Safronkov points to U.S. UN Ambassador Nikki Haley while speaking at a meeting on the situation in the Middle East where the ongoing conflict in Syria was discussed on April 12, 2017-Spencer Platt/Getty