Iraqi Sunni men presented as former jihadists fighting alongside the Islamic State (IS) group who defected to join Iraq government forces take position in Amriyat al-Fallujah, in Iraq's Anbar province, on May 26, 2015. Iraqi forces took up positions on the southern outskirts of Ramadi, officials said, taking two neighbourhoods and moving into Anbar university. Army and police forces as well as allied paramilitaries clashed with IS fighters to take full control of Taesh and Humeyrah, an army colonel said. AFP PHOTO / HAIDAR HAMDANI (Photo credit should read HAIDAR HAMDANI/AFP/Getty Images)National Journal

Even as the U.S. plans to send up to 450 more military advisers to help take back Ramadi from Islamic militants, legislation to authorize the fight against them looks stuck in neutral.

In the 10-month, $2.6 billion war against Islamic militants in Iraq and Syria, Congress' efforts to pass a bill authorizing the use of military force have failed to gain traction, despite some legal experts' claims that the White House shouldn't continue to function under the legal authority granted to fight al-Qaida following the 9/11 attacks.

Some top Democrats want to use the debate to tie President Obama's hands more than he would like, and many top Republicans think he already has the authority to do what he's doing. Few want to weigh in and take ownership of the bloody, complex conflict, outside of Democratic Sen. Tim Kaine and Republican Sen. Jeff Flake, who introduced their AUMF bill this week.

Citing the Pentagon's announcement of deepening U.S. involvement in Iraq, the two Senate Foreign Relations Committee members pushed Wednesday for their bill, which would explicitly provide legal justification for the war and put lawmakers on record about the administration's strategy.

"It sure is evidence of the proposition that the need for an authorization is more urgent," Kaine said in a conference call with reporters. "This is not going away anytime soon. It's not going to be short. It's not going to be easy."

"Let's face it, when you get to 3,500 troops there, then I hope that everyone realizes that the 2001 authorization that provides the authority for the administration now is totally insufficient for this mission," added Flake.

Their bill faces a steep climb in Congress. On Tuesday, Senate Foreign Relations Committee Chairman Bob Corker agreed only to convene a meeting of committee members to discuss if there's a way forward. And Sen. Ben Cardin, Corker's Democratic counterpart on the committee, told National Journal that he doesn't know if the Flake/Kaine bill will even get a vote within the panel. He said he has a "great concern" that the bill leaves the 2001 authorization intact and also believes it needs "further clarifications" to make sure the U.S. doesn't introduce certain ground troops.

"There is discomfort—put it that way—with the way we've moved ahead," said Flake of his fellow Republicans. "There's a concern that if we start this, we've got to be able to finish it and that we don't benefit from airing our differences on this and not having a finished product. I'm sympathetic to those concerns. It doesn't do us well to get into this if we feel that we can't finish it."

In his own statement, Corker said: "Many Democrats want to constrain current and future administrations, many Republicans question the administration's lack of a coherent strategy, and many on both sides believe the White House already has legal authority to combat ISIS. I appreciate the efforts of Senators Kaine and Flake to advance this important issue. The challenge remains that any new AUMF must create enough bipartisan consensus to become law and show that our country is united over the need to confront ISIS."

Obama announced airstrikes against ISIS in August and sent Congress a two-and-a-half page draft for a new war authorization in February, when he pledged to work with lawmakers to repeal the 2001 authorization used to fight ISIS. Last month, House Speaker John Boehner said Obama needed to withdraw his AUMF and "start over." The White House says that it has done its part and it's now up to Congress to craft and pass a new one.

"At some point, the Speaker of the House needs to take responsibility for fulfilling the basic duty of the United States Congress," said White House spokesperson Josh Earnest on Wednesday. "Congress, frankly, shouldn't be ducking the debate."

Earnest also praised the Kaine/Flake bill as a "rare bipartisan effort to fulfill this important congressional responsibility."

Flake and Kaine's bill differs in some aspects but is largely the same as the one put forward by the White House. Both are time-limited to three years and would repeal the 2002 AUMF for the invasion of Iraq. But their bill would rebut the use of "significant" ground troops and supplant the 2001 AUMF as the sole authority for the campaign against ISIS. It also would clarify a bit how the troops would be used: for the protection of the lives of U.S. citizens and to provide "military support" to partners to defeat ISIS. Obama's bill doesn't authorize "enduring offensive ground combat operations," a new term that hasn't been defined.

Above all, both bills wouldn't change what's happening on the ground right now and neither repeals the 2001 AUMF that the administration uses to fight terrorist groups. But Kaine and Flake believe that their bill would show Congress hasn't abdicated its responsibilities during wartime.

"No longer would we be claiming that the 2001 authorization was the legal justification for the battle against [ISIS]," Kaine said. "This [ISIS]-specific authorization would be the complete statutory support."

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