In 2007, then-candidate Barack Obama told the Boston Globe in an interview that no president could authorize military action without Congress unless the U.S. was in imminent danger.
"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," Obama said.
Fast forward six years and Obama sits ready to engage in a military strike against Syria and Congress, though consulted, hasn't held a formal vote authorizing action.
Many argue the U.S. interests are not in any immediate danger, and warn that proceeding without support from Congress could put Obama in a politically uncomfortable position.
More than 150 members of Congress have asked Obama to call lawmakers back from recess, hold a vote, and then proceed from there.
"Though consulting with Congress is helpful, it is in no way an adequate substitute for President Obama obtaining statutory authority from Congress prior to the use of military force, as required by the Constitution," said Rep. Scott Rigell, R-Va., who is leading the effort to get congressional approval.
But many experts say members of Congress have it all wrong. They argue that the War Powers Resolution of 1973 clarifies the Constitution and actually gives the president broader authority to engage in "limited" military action overseas. In such circumstances, they say, Obama doesn't need to get formal authorization from Capitol Hill.
"A limited engagement such as the one tentatively proposed for Syria, involving no troops on the ground and relying on weapons fired from air and sea, does not appear to fulfill the vague criteria for 'hostilities' under the War Powers Resolution," says Christopher McKnight Nichols, a professor at Oregon State University and an expert on the U.S. military history. "Thus the proposed intervention in Syria does not appear to require a deadline for congressional approval or force withdrawal."
Others in the field, however, interpret the president's power under the War Powers Resolution to be much more limited in scope.
Harvard Professor Jack Goldsmith, who worked in the Bush Administration and specializes in the separation of powers, argues the president should not act unilaterally and should "heed his own" advice from 2007. "The White House is mistaken to think that informal briefings to congressional leaders are a substitute, even a near-substitute, for formal public congressional debate and authorization," Goldsmith recently wrote on Lawfare, a national security blog. "Such secret ex ante deliberations lack constitutional significance, and they won't help one bit politically once things go contrary to plan, as they always do."
Michael DiNiscia, associate director of the congressional Brademas Center at New York University, agrees that Congress should be more involved, although he says that it is not legally required. He argues many in Congress would probably like to shirk that responsibility all together.
"You are going to have members of Congress who are speaking up and requesting that any action be first debated by and authorized in Congress. But most of these members of Congress are perfectly happy to not take a tough vote," DiNiscia says. "They would like to reserve the right to complain after the fact."