The White House was ready to share with lawmakers Tuesday its plan to seek authority for the use of military force against the Islamic State group, setting up the first war vote in Congress in 13 years.

Presidential counsel Neil Eggleston was set to address the Senate Democrats’ luncheon, the day before President Barack Obama is expected to formally unveil his proposed authorization, a Democratic official revealed.

The White House and proponents of a new authorization for use of military force argue that passage is important to show unity in the fight against militants who have seized territory in Iraq and neighboring Syria, imposed a violent form of Sharia law and killed U.S. and allied hostages.

To get congressional approval, Obama must find a balance between lawmakers who want wide authority to fight the Islamic State group and others, including members of his own party, who worry that a new authorization to use military force will lead to another American entanglement in a protracted war. The White House has been seeking input from lawmakers before unveiling specifics, in hopes of ironing out differences privately and lining up support from both parties before going public with the request.

So far, no formal language has been submitted, although the White House has completed a draft, according to a senior congressional official who spoke only on grounds of anonymity because this person wasn’t authorized to discuss by name a strategy being discussed privately.

In 2002, Congress passed a resolution authorizing President George W. Bush to use force against Iraq — a vote that scores of Democrats have regretted and then-candidate Obama used as a cudgel against his rivals to win the Democratic presidential nomination.

Obama so far has relied on congressional authorizations that former President Bush used to justify military action after 9/11. Critics say the White House’s use of these authorizations to fight the terrorist group is a legal stretch at best. The president earlier insisted he had the legal authority to deploy more than 2,700 U.S. troops in Iraq to train and assist Iraqi security forces, and conduct ongoing airstrikes against targets in Iraq and Syria. More recently, the president has said he wants a new authorization, but has not released details.

Another congressional official said the president will ask for a three-year authorization so the next president will have to seek renewed authority to fight IS. The official said Obama wants to leave open the option to send in combat forces if needed, but is not seeking an authorization that would permit a prolonged U.S. troop presence on the ground. The White House request also would not restrict the fight to certain geographic locations, but would limit the U.S. to fighting IS militants or any future group that evolves, the official said.

A congressional aide said Democrats will not rubber-stamp the White House version, but will seek to rewrite it to include bipartisan views. Another congressional staffer said the debate in Congress will not necessarily flow along party lines because, for instance, conservative Republicans and liberal Democrats alike have disagreed about two major sticking points: deploying U.S. combat troops and restricting the geographical area served by the new authorization. The second staffer said a final authorization will depend on the language decided on regarding these two issues.

The four congressional officials and staffers spoke on condition of anonymity because they were not authorized to discuss the ongoing negotiations with the White House.

Before Congress ended its last session in December, Sen. Robert Menendez, D-N.J., who at the time was chairman of the Senate Foreign Relations Committee, pushed his version of an authorization that would have limited operations against IS to three years and allowed ground forces in some circumstances. The legislation passed out of the committee, but was never voted on by the full Senate before the session ended.

Menendez said Monday that he has not seen the final language written by the White House, but said more work will need to be done.

“I think a good part of it is how we started in the Senate Foreign Relations Committee,” said Menendez, now the ranking Democrat on the committee since Republicans took control of the Senate in January. “But there is a degree for some greater flexibility than what the Senate Foreign Relations (Committee) drafted.”

Menendez said: “Finding the balance is the challenge here.”

Sen. Orrin Hatch, R-Utah, said the new authorization should be flexible enough so it can be used not only against IS, but also against whatever form the group takes in the future, as well as any groups that associate with or support it materially.

“Most importantly, the authorization should not impose any artificial and unnecessary limitations such as those based on time, geography and type of force that could interfere with our strategic objective of defeating Islamic State,” Hatch said Monday on the Senate floor.

He said he disagreed with those who want to prohibit the use of ground forces or set an expiration date for the authorization.

Other lawmakers want the new war powers to be narrowly defined in a way that gives the president the authority to train and equip local forces and conduct airstrikes, but not launch a combat mission on the ground.

“I’ve been clear in opposition to boots on the ground, but I’d like to see what they propose and hear them out,” said Sen. Brian Schatz, D-Hawaii. “It’s traditional and expected for an administration to articulate their strategy to the Congress, so we want to give them a chance to do so.”

(AP)