Senator Bob Corker, chairman of the Foreign Relations Committee, has been trying to build support for a new Authorization for the Use of Military Force resolution (AUMF) for the last few months.  But the Obama administration insists that the same AUMF that authorized George Bush to invade Iraq can justify the president's Syria policy.

In truth, the current AUMF is vaguely written.  But when Congress passed the measure in 2003, they never dreamed it would be used to justify sending troops to Syria.

Politico:

Absent a new push from the White House, it would be nearly impossible for Corker to reconcile the two parties’ competing hopes for a new war authorization. Democrats want to offer restrictions on any new AUMF beyond Obama’s current authorities, while Republicans don’t want to do anything to tie the administration’s hands. That’s led Corker and ranking member Ben Cardin (D-Md.) to the same conclusion: Nothing, it seems, can pass the Senate.

“To bring up something that highlights a divide over that and maybe makes it appear as if the nation is divided over [ISIL]?” Corker said in an interview on Tuesday. “It doesn’t make a lot of sense to me.”

“We should try to pass an AUMF. But I don’t disagree with Sen. Corker in that the prospects are very, very challenging,” Cardin said. “You have to have a path forward. You can’t just let this meander along in Congress and show division.”

It’s not that Congress hasn’t tried. In the summer of 2013, Obama hauled the Senate back into session to authorize war against Syria over chemical weapons, a push that ultimately stalled. Last December, Foreign Relations Democrats jammed an AUMF through the committee, but the move was too late to secure a floor vote by the full Senate.

And this year, Sens. Tim Kaine (D-Va.) and Jeff Flake (R-Ariz.) introduced their own draft proposal, hoping to jump-start a debate they maintain should have started 15 months ago when the first American bombs were dropped on ISIL.

Even on Tuesday at an unrelated committee meeting, Kaine circulated a letter from 35 House members asking Speaker Paul Ryan to take up a military authorization. Afterward, Kaine said he’s going to keep pressing the case, despite the pessimistic outlook from committee leadership.

“I get it, members of Congress are afraid to cast a vote on war,” Kaine said. “If you want to be real cold about it, if Congress doesn’t support it, then we shouldn’t be forcing people to risk their lives.”

Republicans don't have much of a case.  The "we don't want to tie the president's hands" argument is a non-starter.  The resolution can be drawn broadly enough that President Obama could carry out his campaign against ISIS without hindrance.

What's really at work is that no senator or congressman wants to go on record supporting a potential quagmire.  Meanwhile, the president could use the current AUMF to justify any number of interventions – some that Congress would find objectionable.

That's why they need to go on record in supporting the president's actions in Syria – or not.  We already have a president who scoffs at the Constitution.  Why encourage him by refusing to exercise the war-making powers of Congress?

If the president is seen as defying the Constitution, it is Congress's fault, not his.