Both the White House and Congress are on treacherous turf as lawmakers get ready to vote on whether to mount a military strike against Syria, but many analysts say the executive branch faces the biggest risks — both now and in the future.
Legal experts say the vote on a resolution — which is by no means certain to pass — may set a new precedent for presidential decision-making in future conflicts, and could leave President Obama with no good options in Syria if he does not get the permission he wants.
"This could set a precedent that constrains future presidents," Temple University international law professor Peter Spiro said. "It will make it harder for a president to go it alone in the future."
If the president uses force despite Congress's opposition, and in the face of polls showing widespread public resistance to military action in Syria, Spiro said, "there's going to be a real outcry that will have been magnified by going to Congress."
There also could be legal consequences if Obama acts in defiance of lawmakers. "I do not believe the president would choose to provoke a constitutional crisis by ignoring the will of Congress," said Michael Glennon, international law professor at Tufts University's Fletcher School of Law and Diplomacy.
In recent decades, presidents have asserted significant power to launch limited military strikes without authorization from the legislative branch. Obama himself approved strikes in Libya to support rebels fighting to depose Muammar el-Qaddafi. And he used Congress's 2001 authorization for military force after the Sept. 11 attacks to expand a covert drone program to kill those his administration deems enemy combatants, including American citizens.
Congress has often lacked the will or the ability to push back against independent action by the president.
The constitutional provision that Congress shall have the power to declare war is "largely a nullity," said former Rep. Lee Hamilton, D-Ind., who chaired the House Foreign Affairs Committee and now directs Indiana University's Center on Congress. Lawmakers have not invoked that power since World War II.
Syria may provide an opportunity for Congress to step up to their "constitutional responsibilities" after being virtually "absent" in oversight of drones and silent as the National Security Agency expanded its surveillance and monitoring, Hamilton said.
But as Spiro noted: "It's tough for collective bodies to get their act together "¦ and that's why historically, Congress has looked toothless."
This is the inherent problem with presidents seeking congressional approval after they have already deemed military action in the national interest, especially in an era where everything from deficit reduction to immigration causes gridlock and when decisions must be made quickly.
Obama strongly implied he could act alone last week. "I always reserve the right and responsibility to act on behalf of America's national security," the president said. This insistence, according to Columbia University national security law professor Matthew Waxman, is to avoid creating the limitations Spiro fears.
"By arguing that legally he could go ahead without Congress, [Obama] continues to plant the flag for a broad and assertive executive-branch authority," Waxman said. "Had he not said that, and implied that Congress [granting] authority was necessary, that would not necessarily have bound a future president, but it would have cast more doubt on his broad unilateral powers to launch similar strikes."
A big question remains as to how far Congress, if it passes anything, will go to delineate the parameters of a strike and how much it will leave to Obama. A resolution will be a tough vote for many lawmakers, who will have to answer for it back home in their districts — and in their reelection campaigns.
"Members don't like casting votes like that, whether the votes are about drone strikes or Syria or cyberwar or anything else that could cause constituents to vote against them," Glennon said. "Their whole incentive is to seek credit and avoid blame."