Just Security has hosted a number of interesting exchanges over the last week concerning the international and political implications of identifying the existence of an armed conflict. Ryan Goodman noted the international legal benefits that might attach to identifying the existence of an “international armed conflict” between the US and Syria, and discussed the political repercussions that nevertheless deter Presidents from describing a conflict as “war.” Ryan and Michael Adams took issue with the received orthodoxy on the threshold for the existence of a non-international armed conflict (or NIAC, meaning a conflict with a non-state armed group such as ISIL) and Adil Haque proposed an extremely low standard constrained only by the organized armed group’s “capacity to sustain military operations.” All are laudably focused on the protective benefits that accrue as a matter of international law to applying the rules and enforcement mechanisms of International Humanitarian Law — often referred to in the U.S. as the law of armed conflict — to such scenarios.

Yet beyond the political and international legal ramifications to identifying a state of war or armed conflict, there are significant domestic legal consequences which flow from, and may influence decisions regarding, the determination that an armed conflict exists. First, to Ryan’s point that political ramifications of identifying actions against Syria, or any state, as “war” may hinder President’s from doing so, I would add that the use of that term raises domestic legal consequences for the separation of powers between the President and Congress. Second, in response to arguments favoring a lowered threshold for determining the existence of a non-international armed conflict, I highlight some significant domestic dangers as well. The U.S. President relies upon the existence of an armed conflict for a host of domestic powers to take actions that domestic law would otherwise prohibit in the absence of such a conflict. Lowering the threshold for determining the existence of an armed conflict thus lowers the threshold for the use of those powers.

I. Domestic legal consequences of asserting a “war” with Syria 

First, I’ll address the domestic legal concerns that supplement Ryan’s discussion of the political ramifications of identifying the conflict with Syria, or any state, as “international armed conflict,” versus “war.” The domestic legal terminology of war differs in many respect from the international legal terms. Formal domestic law speaks of “war” and “hostilities” and neither term maps perfectly onto the international law concept of “armed conflict.” As a matter of domestic law, of course, the Constitution grants Congress the power to declare war. But a Congressional statute, the War Powers Resolution, recognizes that the President may enter into “hostilities” without such a declaration, so we are to understand that hostilities must identify a lower threshold of activity than “war” in the domestic sense. Neither term is defined by these documents. In lieu of such legislated definitions we have a history of executive branch practice, punctuated by OLC legal opinions, and testimony by executive branch officials, none of which suggests that either term is defined by the international law concept of “armed conflict.”

These distinctions add some legal consequence to Ryan’s point about Presidents’ reticence to identify a conflict as “war.” Labeling at least a President’s offensive actions as initiating a “war” could suggest that such actions required prior authorization by Congress. In the case of a conflict with Syria, the President does not have, or claim to have, such authorization.

II. Domestic legal consequences of lowering the threshold of “armed conflict”

Regardless of the characterization of a conflict as “war,” the status of “armed conflict” itself has significant legal ramifications for the President’s domestic powers. The President relies upon the existence of an armed conflict in order to take many actions that would not be permitted in its absence. Many of these actions also require some basis in congressional authorization, but the scope of that authorization, and the scope of the constitutional limits on presidential authority, necessarily turn on the existence of armed conflict.

For example, although the Constitution generally prohibits long-term administrative detention without charge, the Supreme Court has confirmed that the existence of an armed conflict allows such detention of persons who are part of enemy forces. The Executive has asserted authority to deliberately track, target and kill such enemy forces in a way that would be unconstitutional outside of armed conflict, except in extreme circumstances of exigent self-defense. The use of military commissions, too, ordinarily depends upon the existence of armed conflict, and so, too, does the seizure of enemy property.

I do not by any means intend to suggest that these domestic law implications dictate the appropriate international law threshold for the existence of an armed conflict. But for those weighing the benefits and potential dangers of a much lower threshold, it is worth considering the increased power to the President (and the changed balance of powers in many other states) that is predicated on the existence of armed conflict.

As a practical matter, this is only a modest concern when it comes to traditional international (state-to-state) armed conflict or even for internal non-international armed conflict (civil wars). Historically, as Ryan notes, states have been hesitant to recognize the existence of armed conflict in such contexts even when the reality has been clear. But the age of “global” or “transnational” non-international armed conflict brings a different set of pressures. Politics may weigh more in favor of declaring an armed conflict with a nonstate terrorist group than with another state. The increased domestic powers the U.S. President enjoys when acting within the context of an armed conflict may well further nudge toward, rather than against, identifying a scenario as such.

It is thus not fanciful to imagine that international legal support for a lower standard would further encourage, and indeed legitimize, executive claims to greater power. Depending on how much the threshold is lowered, this could result in an increased extension of an armed conflict label, and thus powers, to contexts that would not have previously been treated as such.

An alternative, of course, is to disentangle the two sets of laws, such that U.S. domestic authorities do not turn on whether the international law standard is met–though international law is certainly a sensible place to look. This would entail carving out a clear domestic law standard for determining the existence of armed conflict, and convincing courts of an approach that does not have a foundation in the laws of war.

Conversely, one might amend slightly the international law proposal: employ a lower standard for triggering the IHL rules whenever military force is employed transnationally against a non-state actor, divorced from the actual existence of armed conflict. (For example, US forces explicitly employ a lower standard for applying IHL rules already as a matter of policy.)

But in contemplating such alternatives, we should remain aware of the reality and risk of the way such international law limits have legitimized domestic power in the past. Historically and continuing today, as I’ve explored here, the US Executive has relied upon the existence of international law constraints in order to soften its claims to domestic power, particularly in times of war. And the courts and Congress have relied upon those international law constraints—which are often more permissive than the ordinary constitutional rule—in acquiescing in the President’s increased claims to power. There is every reason to assume that, should international law establish a lower threshold for the application of IHL, future Presidents would point to the existence of these international law constraints to mollify concerns about enhanced domestic claims to power in precisely the same way.