Would a US Military Intervention in Syria be Constitutional?

The US and its allies are considering a military intervention in Syria in response to the Assad regime’s use of chemical weapons against civilians. If President Obama decides to go in, it will likely be without congressional authorization. Such a step would create serious constitutional problems similar to those arising from the intervention in Libya in 2011.

Article I of the Constitution reserves the power to declare war to Congress alone. Thus, any military action large enough to constitute a war requires congressional authorization. The president can, of course, defend against an actual or imminent enemy attack without waiting for Congress. In that scenario, a state of war would already exist independent of any US action. But the Assad regime has not attacked the US and does not seem likely to do so in the near future. Everything I said in this 2011 National Review symposium essay on the Libya War applies with equal force to a possible strike on Syria:

Article I of the Constitution unequivocally gives Congress, not the president, the “power . . . to declare War.” The Founding Fathers sought to avoid a situation where one man had the power to commit the nation to war by himself. Even Alexander Hamilton — the biggest supporter of sweeping presidential power among the framers of the Constitution — recognized that “the Legislature have a right to make war” and that “it is . . . the duty of the Executive to preserve Peace till war is declared…”

Some small-scale uses of force may not rise to the level of a war and therefore can be undertaken by the president alone under his authority as Commander in Chief of the armed forces. President Reagan’s 1986 airstrike on Libya might be an example, as were Bill Clinton’s 1998 missile strikes against al-Qaeda base camps. If the Libya intervention remains limited to a small number of missile attacks and airstrikes, perhaps it can be justified on the same basis. However, it seems possible that the administration plans to go beyond this….

There is some ambiguity about exactly where a small-scale “conflict” ends and “war” begins. But the fact that we cannot draw a precise line between the two does not mean that there aren’t cases that clearly fall on one side or the other. We can’t draw a precise line between people who are “short,” those who are of “average” height, and those who are “tall.” But we can still easily recognize that Shaquille O’Neal is tall. Similarly, a large-scale military action against a foreign government clearly qualifies as “war.”

It is possible that the administration envisions only a small-scale strike that doesn’t rise to the level of a war. But it seems unlikely that Assad will give in as a result of such a small attack or even decide to abjure the use of chemical weapons. If success is possible at all, it will probably require larger-scale military action. If so, the Constitution requires the president to get congressional military authorization. Then-candidate Obama recognized as much when he wrote in 2007 that “The President does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation.” There are also good practical reasons to avoid starting a war without congressional support.

Although I am more willing to support military intervention than some libertarians, I have serious practical doubts in this case, because the opposing sides in the Syrian Civil War are roughly equally bad and equally anti-American; it is not in our interest for either of them to prevail. Be that as it may, the administration should at least not initiate military action without congressional authorization. Both prudence and the Constitution cut against unilateral executive action here.