President Obama's pursuit of congressional authority for a Syrian strike operation is, to date, his single most important decision in reshaping the post-9/11 presidency.
He early foreswore torture and declared the U.S. bound by the Geneva Conventions in the war against al Qaeda. These orders, however, only institutionalized legal positions into which the Supreme Court had already pushed the Bush Administration. Guantanamo, despite Obama's best efforts, is still open.
But seeking authorization for a military strike against Syria marks the first time that a modern-day president has taken the initiative to elicit legislative approval for a military action that, by the President's own reckoning, will neither be a prolonged, nor a boots-on-the-ground operation.
In announcing his decision, President Obama, like both Presidents Bush, declared that he possessed the constitutional authority to act unilaterally. He said he does not need Congress' approval in order to proceed.
But historical precedents have consequences. Whatever their formal legal views, the Bushes' decisions helped cement a consistent pattern: With the exception of Korea, the United States has never engaged in a massive or prolonged military deployment without some form of explicit congressional sanction. A President acting unilaterally to start what is sometimes called "a real war" henceforth would probably be courting impeachment.
Since World War II, presidents (except for Eisenhower) and their lawyers have consistently maintained that executive power encompasses unilateral presidential authority to deploy military force wherever the President thinks necessary to protect the national security of the United States. As well documented by Tulane law professor Stephen M. Griffin, however, presidents made no such ambitious claims prior to World War II. It was common for high public officials, including presidents, to say the contrary.
The modern argument generally takes either of two forms. One, elaborated by the State Department during the Vietnam War, is a kind of "living Constitution" argument. There is scholarly consensus that the Constitution intended for the President to have the authority, without advance congressional approval, to repel sudden invasions. The State Department argued that, under modern conditions, threats to U.S. national security anywhere in the world could be as urgent as the threat of an invasion would have been in 1789. Hence, the allocation of war-making authorities should now be understood to give the President unilateral war-making power that matches the scope of modern threats.
The second form of argument is that unilateral presidential power to conduct at least those military operations that fall short of "real war" has been ratified by Congress' implicit acquiescence in presidential actions of just this sort. In other words, presidents have acted without Congress, and Congress has not barred the practice. The War Powers Resolution is sometimes argued as supporting this view because it effectively permits the President on his own initiative to commit armed forces to combat for up to 60 days.
Neither of these arguments is frivolous, but each departs notably from the original Constitution. Because the Constitution vests authority in Congress to issue "letters of marque and reprisal" -- basically, licenses to private parties to attack and capture enemy vessels -- it is evident that the framers supposed congressional authority necessary to the deployment of military force even on a small scale.
A version of the history-based argument is, however, at least technically reconcilable with the original understanding. Congress' acquiescence can be understood as a form of congressional authorization, which still remains a necessary legal precondition for any presidential military initiative.
The problem for Obama regarding Syria, however, is that -- as scholars as different in political orientation as Jack Goldsmith and David Cole have pointed out -- no historical precedent quite resembles the punitive strike that the President seeks to inflict. There is no imminent danger to U.S. persons or property. We are not acting at the behest of the sitting government. We would not be acting in pursuit of any resolution of the U.N. Security Council. It could not even be argued, as with Kosovo, that the strike was necessary to reaffirm the cohesiveness of NATO. Proceeding without either clear domestic precedent or obvious defense under international law would come close to saying that the President's authority to deploy military force is beyond legal limit.
In seeking congressional authorization, President Obama is thus re-submitting the modern presidency to the kind of "cycle of accountability," to use Professor Griffin's phrase, that the constitutional design anticipated. We will strike Syria, if at all, based on a joint determination by both elected branches that should nurture an ongoing sense of joint responsibility to monitor and assess in a careful way whatever consequences ensue.
It is all the better for this purpose that support for a resolution, if enacted, will necessarily be bipartisan. No party and no elected institution will be able to say, in the face of adverse consequences, "We didn't do this."
It is also a strategy under which the President accepts political risk. If Congress votes down a resolution that would authorize a strike action, the President might take the position that (a) failure to pass a resolution of authority does not equal the affirmative passage of a resolution denying him authority, and (b) absent the latter, he still has constitutional power to undertake the mission unilaterally. But it's not likely to be a politically viable argument. If Congress fails to authorize a Syria strike, the President is all but certain to desist - with obvious negative consequences for his credibility, both at home and abroad.
Of course, historical precedents are not legal precedents like Supreme Court opinions. The norm of consistency across cases is not as strong in decision making where politics dominates.
But events, when they happen, exert a force on the future. Should President Obama or his successors seek to attack other nations in similar circumstances in the future -- Iran, for example, to forestall its nuclear ambitions - the question will be asked, "Why can't Congress be involved, as it was in Syria?" This is an institutionally powerful question. It can limit the exertion of power. It will have force in rebalancing the allocation of authority between executive and legislative branches in the deployment of U.S. military assets in support of presidential foreign policy.
In the world of constitutional politics, this is a very big deal.
Follow Peter M. Shane on Twitter: www.twitter.com/petermshane