President Obama has yet to say what course of action he'll take to respond to the alleged use of chemical weapons by President Bashar al Assad's regime in Syria, but his administration has previewed the justification it will use if Mr. Obama decides to take military action.
Mr. Obama on Wednesday said he has "no interest in any open-ended conflict in Syria." However, he added, "we do have to make sure that when countries break international norms on weapons like chemical weapons that could threaten us, that they are held accountable."
To launch an assault against the Assad regime that meets domestic legal standards, Mr. Obama's actions would have to pass constitutional muster and meet the statutory requirements set by the 1973 War Powers Resolution.
Before taking over the executive branch, Mr. Obama and Vice President Joe Biden strongly asserted that the president's ability to use military force is constrained by Congress. Yet since Mr. Obama took over the White House, the administration hasn't shied away from unilaterally deciding to take limited military action.
Mr. Obama's approach follows one that presidents have taken since the end of World War II, when administrations started exercising their war powers more independently. Some administrations have argued the War Powers Resolution is unconstitutional, but the Supreme Court has never weighed in on the issue -- leaving the extent of the president's war powers an open question.
"Part of the problem is these are legal issues, and legal issues are settled in court at the end of the day," James Lindsay, a senior vice president at the Council on Foreign Relations, told CBSNews.com. "And when courts choose not to adjudicate it, people are free to lay down their interpretation of the rules."
Predictably, when it comes to war powers, the president has the political advantage -- he is, after all the commander in chief. Congress, however, has the constitutional authority to declare war, so legislators do their best to keep the president's powers in check.
As a senator and presidential candidate in 2007, Mr. Obama said, "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. In instances of self-defense, the president would be within his constitutional authority to act before advising Congress or seeking its consent."
Biden, also a senator and presidential candidate in 2007, said he would move to impeach President Bush if he unilaterally attacked Iran because of its nuclear programs.
In 1998, Biden said on the Senate floor, "To be sure, the commander in chief ensures that the president has the sole power to direct U.S. military forces in combat. But that power - except in very few limited instances - derives totally from congressional authority."
Yet in 2011, the administration took military action in Libya without any congressional approval, prompting the Republican-led House of Representatives to vote to rebuke the president.
In its legal justification for action in Libya, the Justice Department's Office of Legal Counsel (OLC) argued that Congress' authority to declare "war" was limited by the definition of war. "This standard generally will be satisfied only by prolonged and substantial military engagements, typically involving exposure of U.S. military personnel to significant risk over a substantial period," the OLC wrote.
The OLC augmented that argument by noting the operation in Libya would be limited to air strikes in support of a United Nations resolution, and that no American lives would be put at risk. And while Mr. Obama in 2007 said the president could only act unilaterally in a matter of self-defense, the OLC in 2011 justified the use of force in Libya as "in the national interest."
University of Texas Law School professor Robert Chesney, a scholar at the Robert S. Strauss Center for International Security and Law, told CBSNews.com that when it comes to the administration's justification for action in Syria, "There's just no doubt they have already or will take the same position here. You can't imagine anything other than that same argument."
While military action in Syria would be based on a legal argument similar to the one given for Libya, the U.S. this time would have to act without the backing of the United Nations. Chesney said the situation now is more comparable to President Clinton's use of force in Kosovo in 1999.
"In Kosovo, there was a clear humanitarian justification," Chesney said. "What a lot of people said at the time was that it was 'illegal but legitimate.'"
The administration this time around has called the use of chemical weapons a "moral obscenity" that violates international norms, threatening U.S. interests.
"We want to make sure that a response sends an unambiguous signal to the Assad regime and to dictators around the world that living up to these international norms is the firm expectation of the international community, and that failure to do so has serious consequences," White House spokesman Josh Earnest said Thursday.
Earnest on Thursday also said that any action the administration will take in Syria will be "very discrete and limited" in scope -- implying it could fall within the bounds of the War Powers Resolution. The 1973 statute says that the president must consult with Congress before introducing armed forces into hostilities, and after 90 days, it must have explicit congressional approval to keep them there.
The effectiveness of the War Powers Resolution, which historian Arthur Schlesinger, Jr. famously referred to as "toy handcuffs," is arguably negligible. Past administrations have pushed back against the law in various ways, including by arguing with Congress over the start of the 90-day countdown.
"Who starts the clock? What starts the clock? This was a big issue in the 1980s with various deployments," Lindsay said. "Whether sending troops abroad started the clock, the actual use of force... The law was not especially well written."
With that sort of ambiguity, and no court ruling to settle legal disputes over war powers, "You will ransack history for whatever arguments you can find to bolster your case," Lindsay said. "A lawyer's history tends to be selective."