The White House is calling on lawmakers to work out their yawning divisions over an authorization to use military force against Islamic State militants and says President Barack Obama is open to changes to his initial proposal.

Obama wants authorization to pursue the violent extremist group across international boundaries, but would be willing to accept amendments to much of the rest of his draft, the White House says. That includes his proposed three-year time limit on U.S. military action and the most contentious language over the use of American troops.

“It’s their turn to take the lead and to walk it through the legislative process,” White House press secretary Josh Earnest said as Congress returned to Washington on Monday after a weeklong holiday break.

Some Republicans say Obama’s proposal is too restrictive for the mission to succeed. On the other side, some Democrats want more limitations on Obama’s authority so they don’t end up authorizing another open-ended war.

Senate Foreign Relations Chairman Bob Corker, R-Tenn., plans to hold hearings on the legislation over the next couple of weeks and said he’s keeping options open on the best way to proceed. He said options include amending Obama’s proposal or to “start whole cloth from a clean fresh beginning.”

“The most important thing for the Senate and Congress and the American people to see is that the administration has a plan, that it’s real,” Corker said. “Now they are seeking something, so it’s incumbent on them to come up and lay out a way forward.”

Obama argues he doesn’t need a new authorization to pursue Islamic State terrorists legally — and he’s been launching strikes against them for months based on authorizations given to President George W. Bush after the Sept. 11 terrorist attacks. But critics say Obama’s use of those authorizations is a stretch at best, and the White House is now making clear that it doesn’t see reliance on that authority as ideal, either.

The White House now says if a new authorization is signed into law, Obama will no longer rely on the authority approved in 2001 to pursue the Islamic State group and instead rely solely on the new powers.

“I’m not at all going to be surprised if there are members of Congress who take a look at this legislation and decide, ‘Well, I think there are some things that we should tweak here, and if we do, we might be able to build some more support for,’ ” said Earnest. “So I think it is fair for you to assume that this reflects a starting point in conversations.”

California Rep. Adam Schiff, the top-ranking Democrat on the House Intelligence Committee, has been pushing the White House to include a sunset of the 2001 authorization as part of the new debate.

“I’m very skeptical about our ability to rewrite the 2001 authorization after we go through a debate on the ISIL operation,” Schiff said. “I’m not sure we have the appetite to go through another round.”

Obama has said he wants to refine and ultimately repeal the 2001 authorization. But besides the Islamic State campaign, the president also is using the law as the legal basis for the continued operation of the detention center at Guantanamo Bay and attacks on militants in Yemen and elsewhere.