In Washington, the House and Senate are in deliberation after the president’s request for authorization to use force against Bashar al-Assad’s regime in Syria. Beyond the obvious lurks another issue in contention: Congress’s sole authority to declare war.

Following Secretary of State John Kerry and Secretary of Defense Chuck Hagel’s testimony before the Senate Foreign Relations committee Tuesday, Sen. Rand Paul (R-Ky.) raised the possibility of a filibuster. “I can’t imagine that we won’t require 60 votes on this,” Paul said in a conference call with reporters. “Whether there’s an actual standing filibuster, I’ve got to check my shoes.”

As it stands at the time of the drafting of this article, it is not clear if the resolution will have enough votes to pass, lest with 60 votes needed to clear the filibuster challenge. As of 9 AM EDT Wednesday, the Senate had 20 confirmed ‘yes’ votes for a resolution to authorize an American response to Syrian use of chemical weapons to 10 confirmed ‘no’ votes, according to CNN.

This begs an interesting question: what keeps the White House from acting as it chooses, regardless of Congress’s decision on the resolution? Kerry, in his testimony to the Senate, made it perfectly clear that the administration will act, with our without Congressional approval.

“We all agree there will be no American boots on the ground — the president has made crystal clear, we have no intention of assuming responsibility for Syria’s civil war,” Kerry said. “But this is not the time for armchair isolationism. This is not the time to be spectators to slaughter. Neither our country nor our conscience can afford the cost of silence.”

Constitutional ambiguity

At the core of the White House’s argument is the War Powers Resolution of 1973, which in effect limits the president’s ability to direct the military in aggressive actions abroad. In particular, 50 U.S.C. § 1541(c) states:

“The constitutional powers of the President as Commander-in-Chief to introduce United States Armed Forces into hostilities, or into situations where imminent involvement in hostilities is clearly indicated by the circumstances, are exercised only pursuant to (1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.”

Since its introduction, the White House has held this to be unconstitutional. The Executive Branch’s argument centers around the notion that Congress is attempting to exert control of the military in a situation where no war has been declared, in violation of the “separation of powers” doctrine. By forcing the Executive Branch to present casus belli (“reasons for war”) to Congress, Congress is exerting de facto control of the military and making the president subordinate to its wishes. Even if war has been declared, constitutional scholars have argued that Congress has no constitutional authority to direct military action except in the case of capturing territory or licensing state-authorized piracy.

The powers of the office of Commander-in-Chief is recognized as needed by the presidency to effectively “defend the Constitution.” In regard to ultimate authority of the military, however, the Constitution is less than clear. The president has formal and final command of the national military, according to the Constitution, but it is Congress’s responsibility to provide and maintain a navy and to raise and support the army. This reflects the notion of shared responsibility for the national defense.

It becomes even more complicated and controversial when one factors in the fact that under the Presentment Clause, all acts of Congress — with the exception of adjournment and impeachment — must bear the approval of the president, or failing that, two-thirds of both houses.

In all reality, should the War Powers Resolution ever be formally tested before the courts, it would likely be struck down. The fact that it hasn’t reflects an ‘understanding’ between Congress and the White House, in which the president will keep Congress advised of foreign military actions and not fight “secret wars,” while Congress will not compromise military operations — for example, by cutting off military appropriations.

The power of rhetoric

The Obama administration, however, has taken this one step farther. The administration has argued, the question of its constitutionality aside, that the War Powers Resolution doesn’t apply to it. The administration argues that it is not involved in “hostilities,” as it is presented in the law.

The Merriam-Webster Dictionary defines “hostility” as

1 a: deep-seated usually mutual ill will b: (1) hostile action (2) plural: overt acts of warfare. 2: conflict, opposition, or resistance in thought or principle.

By this definition, the president’s proposed action of bombing Syrian government installations qualifies as a non-friendly act of aggression — in other words, as “hostilities.”

Not everyone agrees with this. Many have argued that a punitive action, such as responding to a violation of international law, does not constitute a hostile action, but a corrective one. “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,” said 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.”

This argument begs a new question: what exactly gives the United States unilateral power to correct or punish a sovereign state? This, fundamentally, is the underlying ambiguity that has defined American foreign policy in the modern era. It is an ambiguity unlikely to be resolved anytime soon.

“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,” said Michael DiNiscia, associate director of the congressional Brademas Center at New York University, prior to the referral of the Syria resolution to Congress. “They would like to reserve the right to complain after the fact.”

Meanwhile, in Congress…

The Senate resolution, drafted by Sens. Robert Menendez (D-N.J.), the chairman of the Foreign Relations Committee, and Bob Corker (R-Tenn.), the committee’s ranking member, restricts U.S. involvement in Syria to 60 days — with a one-time possible extension of 30 days — and bans the involvement of ground troops in the operation.

“Together we have pursued a course of action that gives the President the authority he needs to deploy force in response to the Assad regime’s criminal use of chemical weapons against the Syrian people, while assuring that the authorization is narrow and focused, limited in time, and assures that the Armed Forces of the United States will not be deployed for combat operations in Syria,” Menendez said in a statement.

Paul, who has became endeared in libertarian circles because of his filibuster against the president’s domestic use of drones last year, may be motivated in launching a formal filibuster simply to make clear his opposition to American foreign intervention, but he seems aware that there is little hope in stopping the resolution in the Senate. With the leadership currently non-committal, there is no guarantee that a formal challenge from the Senate Republicans will be raised, and with Sen. John McCain (R-Ariz.) supporting the resolution, it is likely that the otherwise mainstream Republican will follow suit.

“I think our best chance for ultimate victory is in the House,” said Paul.

In the House, the Republican leadership — particularly, Speaker of the House John Boehner (R-Ohio) and House Majority Leader Eric Cantor (R-Va.) — has expressed support towards the president’s call for a resolution, although initial reports have indicated that the House version will limit intervention to 60 days without the possibility of extension.

However, uncertainties from both sides of the aisle — long-held suspicions from Republicans toward the president and resistance to another foreign war from Democrats — make passage of the resolution less than a sure thing.

“We understand why many of our GOP colleagues are undecided about a use-of-force resolution. Indeed, we have reservations about the president’s implied course of military action,” wrote Reps. Tom Cotton (R-Ark.) and Mike Pompeo (R-Kan.) in an op-ed in the Washington Post. “Yet Congress has its own constitutional duty to defend U.S. interests, and those interests shouldn’t be neglected simply because we have doubts about Obama.”