(Photo by Mike Theiler/Reuters) President Obama and Vice President Biden. (Photo by Mike Theiler/Reuters)

President Obama's decision to seek authorization for the use of force against Syria has serious implications for his presidency, but it is unlikely to change the way presidents deploy the military abroad in the future.

The outcome of this month's vote will clearly affect the public perception of Obama's influence, both at home and overseas. As Sen. John McCain (R-Ariz.) put it Monday, "If the Congress were to reject a resolution like this, after the president of the United States has already committed to action, the consequences would be catastrophic, in that the credibility of this country with friends and adversaries alike would be shredded.”

But will future presidents be compelled to seek congressional approval for limited military strikes? That seems unlikely.

The question of whether to punish Syria for using chemical weapons comes not only at a time when congressional-White House relations are strained, but when Americans are weary of the wars in Iraq and Afghanistan, and even Britain has declined to join in any strike. In this instance, according to presidential historian Robert Dallek that meant Obama "had no choice but to ask Congress for a resolution of support. To have done otherwise would have opened him to a lot of congressional criticism and added to existing difficulties that make it so difficult for him to get their cooperation."

The nation's political climate has always influenced whether presidents have sought congressional approval. Dallek noted in an e-mail that Franklin D. Roosevelt could not get Congress to alter the Neutrality Acts in 1939 on the eve of World War Two, but two months after the war commenced, he won lawmakers' support. Shortly before the attack on Pearl Harbor Roosevelt declined to ask Congress for a declaration of war "for fear he couldn't win sufficient backing to ensure a stable consensus for fighting," Dallek wrote, but he won nearly unanimous approval for a war declaration after the strike.

"My point is that there have been so many variations on how presidents have dealt with Congress in responding to foreign problems that it is difficult to say that there are any hard and fast rules at this point on what is appropriate or required," he added. "Each circumstance calls forth a different response."

George W. Bush, for example, sought congressional approval for military action in the wake of the Sept. 11, 2001 attacks against the World Trade Center and the Pentagon, when the nation was relatively unified in its determination to confront threats from abroad. He obtained an authorization for the use of military force against terrorists just days after the Sept. 11 attack, which provided the basis for the Afghanistan invasion, and got a resolution for war against Iraq in 2002.

Under the 1973 War Powers Resolution, the president must obtain congressional authorization in the form of a joint resolution before committing the nation to war. Under the law the president must notify Congress within 48 hours of committing the military to action and U.S. armed forces cannot remain in action for more than 60 days, allowing for a 30-day withdrawal period, without either congressional approval or a formal declaration of war.

But presidents have embarked on open-ended military strikes in the past without congressional authorization: President Clinton did it in 1999, and Obama committed the U.S. to NATO's strikes against Libya in 2011 without a congressional vote.

In the past few decades, presidents "have been pretty successful at avoiding their obligations" under the law, said Stephen Hess, senior fellow emeritus at the Brookings Institution.

"This is the exception to the rule, rather than the rule," Hess said in an interview. "One would assume that future presidents will go back to business as usual."

The fact that congressional leaders are now coalescing around the idea of a strike may encourage future presidents to seek lawmakers' approval, but it appears more likely that Obama's successors will make that call on a case-by-case basis.

In fact, Hess observed, the vote may tell the public as much about divisions within the Republican Party, which is currently split between an isolationist wing and one more inclined to intervene abroad. And for academics, he added, the current debate offers a great case study of the War Powers Act.

"For political scientists it’s a very attractive moment, in which you can figure out how the system would have worked had anyone bothered to pursue it," he said.

There is one way in which Obama's approach to Syria may influence future presidents: his pronouncement that using chemical weapons would cross a red line helped set in motion current events, though some argue the international norm against using chemical weapons has influenced the president's thinking more than his "red line" pledge.

"It does suggest for any president that words matter. If he hadn’t talked about red lines we wouldn’t be in this situation," Hess said, adding that future chief executives might take the following lesson from Obama's example: "Shut up--unless you are willing to accept the consequences for what you’ve just said."