WASHINGTON — For the first time since taking office, and six months after beginning airstrikes against the Islamic State in Iraq and Syria, President Obama plans to ask Congress on Wednesday to approve U.S. military action against the militant group.

The proposed new Authorization for the Use of Military Force against the Islamic State “and associated forces” includes no geographic limitations, in keeping with the administration’s description of the group as seeking expansion beyond Iraq and Syria, and the Islamic State’s own claim to head a “caliphate” spanning the Muslim world.

The White House language prohibits the “enduring” deployment of U.S. ground forces, but it does not specifically ban limited boots on the ground if the president determines they are necessary, according to a senior administration official and lawmakers who have been briefed on the proposal. The official, who like others spoke on the condition of anonymity to discuss the proposal, said the terminology refers to the use of Special Operations forces and other discreet missions.

The approval would expire in three years, allowing a new president and Congress to decide whether it needs to be extended or expanded.

It would also repeal the 2002 AUMF under which George W. Bush invaded Iraq but would leave in place the 2001 authorization against the al-Qaida perpetrators of the Sept. 11, 2001, attacks. Both have been cited by the Obama administration as legal justification for its military action in Iraq and Syria.

The proposed new authorization provides the first opportunity for Congress to fully debate those operations. It comes nearly two years after Obama first said that he would seek new congressional approval for action against newly rising international terrorist groups. When he authorized airstrikes in the summer against the Islamic State, the president repeated his desire for new authorization.

But Congress and Obama differed on who should take the lead on proposing new language, with each calling on the other to go first. Lawmakers have introduced and debated several bills that drew neither bipartisan agreement nor administration approval.

Congressional differences emerged in stark relief in December, when the Democratic-led Senate Foreign Relations Committee split along party lines to approve a bill that never made it to the floor. While Democrats argued in favor of the bill’s time limit and a prohibition against boots on the ground, Republicans said such restraints would tie the president’s hands in dealing with the Islamic State threat.

It was only last month that the White House shifted into high gear, consulting with leading lawmakers and composing its own preferred language.

The relatively broad parameters of Obama’s request appears designed to address the competing interests on both sides of the aisle.

Republicans have warned that debate could take several months. Senate Majority Leader Mitch McConnell, R-Ky., plans to huddle with his members Wednesday afternoon once the White House formally releases the request, while the GOP chairmen of the House and Senate armed services and foreign relations committees are preparing for hearings that will ask for testimony from top Pentagon leaders and Secretary of State John Kerry.

“What people want to fully understand is a plausible way forward toward success,” Sen. Bob Corker of Tennessee, who chairs the Senate Foreign Relations Committee, told reporters Tuesday, adding: “It won’t be something that by any chance will be marked up quickly.”

“I don’t think there’s any rush,” he added later, because “it’s not as if the language is going to change our activities on the ground at present, is it?”

Two Democrats who introduced authorization language last year said they were pleased with the administration effort but had problems with some of the language.

“My first reaction is ‘finally, thank goodness,’ ” said Sen. Timothy Kaine, D-Va. “We’re in our seventh month of war, and we’re going to finally have this discussion.”

Kaine said he supported the sunset provision in the authorization and could live with the lack of geographical limitations. But among his concerns, he said, is ground troops language that “is too vague for me. We learned from the 2001 authorization that vagueness is bad.”

The 2001 AUMF has been used by Obama, and was used by Bush before him, to provide legal justification for military action against groups “associated” with al-Qaida that are largely independent of it, including the Islamic State, in a number of different countries.

“Second, you’ll see a lot of questioning” about the U.S. mission in Syria, Kaine said.

Rep. Adam Schiff, D-Calif., who proposed authorization language in the House last year, said he, too, would like to see the prohibition on troop deployments “more narrowly drawn, both in terms of the use of ground troops and putting a geographic limitation on the use of force. … What they have in mind is still fairly broad and subject to such wide interpretation that it could be used in almost any context.”

Schiff also questioned the lack of a sunset provision on the 2001 al-Qaida authorization. “Given the history” of its use to expand presidential war-making power, he said, “I think we have to be careful.”

But others will be pushing for an open-ended authorization, including Sen. John McCain, R-Ariz., who chairs the Senate Armed Services Committee. McCain said Tuesday that he would support a new authorization only if it places no restrictions on troop movements.

After months of consultations with lawmakers in both parties, the White House on Tuesday dispatched Chief of Staff Denis McDonough and chief counsel Neil Eggleston to a weekly luncheon for Democratic senators in hopes of winning their support.

But emerging from the meeting, Senate Minority Leader Harry Reid, D-Nev., said that the proposal “is the opening salvo; there’s nothing finalized yet.”