WASHINGTON — The Obama administration has told lawmakers the president will seek formal authorization to fight the Islamic State that would prohibit the use of "enduring offensive ground forces" and limit engagement to three years. The approach offers what the White House hopes is a middle way on Capitol Hill for those on the right and left who remain deeply skeptical of its plans to thwart extremist groups.
The request, which could come in writing as early as Wednesday morning, would open what is expected to be a monthslong debate over presidential war powers and the wisdom of committing to another unpredictable mission in the Middle East while the nation is still struggling to cope with the consequences of two prolonged wars.
Congress has not voted to give a president formal authority for a military operation since 2002, when it backed George W. Bush in his campaign to strike Iraq after his administration promoted evidence, since discredited, that Saddam Hussein's government had unconventional weapons.
The new request to conduct military operations would repeal Bush's authorization. But it would leave in place the broad authority to counter terrorism that Congress granted him in 2001 after the Sept. 11 attacks, which many Democrats found troubling.
After more than a decade of war and 7,000 US military lives lost in Iraq and Afghanistan, President Obama will face doubts — not only from Democrats who want stricter limitations set on where he can send troops and how long his authority will last but from Republicans, who are dubious of the administration's strategy for defeating the Islamic State extremist group.
The White House has tried to address concerns by drafting a resolution that tries to be both circumscribed and flexible. It would explicitly disallow extended use of combat forces, lawmakers and aides who are familiar with the plan said Tuesday. That language is intended as a compromise to ease concerns of members in both interventionist and noninterventionist camps: those who believe the use of ground forces should be explicitly forbidden, and those who do not want to hamstring the commander in chief.
The resolution also requests authority to wage battle beyond the fight against the Islamic State to include "associated forces." It would contain no geographic limitations. Both are sticking points for many Democrats, who expressed concern the president was setting the country up for another open-ended conflict.
Those tensions surfaced Tuesday as Obama's chief of staff, Denis McDonough, visited the Capitol to present Democrats with the outlines of the language the White House plans to send to Congress. By most accounts, he faced a skeptical audience.
Senator Richard Blumenthal, Democrat of Connecticut and a member of the Armed Services Committee, said he had "grave reservations" and had "yet to be convinced."
Senator Joe Manchin III, a West Virginia Democrat, echoed the concerns of many lawmakers who worry that giving the president approval will reward a decade of mismanagement in the Middle East.
"If money or military might would change that part of the world, we'd be done a long time ago," he said. "In West Virginia, we understand the definition of insanity."
The Obama administration has insisted it does not need Congress's authority to continue its military campaign. But an affirmative vote in Congress would bolster the legitimacy the president already claims as commander in chief in the battle against the Islamic State and confer a stronger legal underpinning for his actions.
Many Republicans, despite opposing Obama on almost every other issue, seem willing to give him that authority.
"I have disagreements with the president's conduct of foreign policy and what he's done," said Senator Jeff Flake, Republican of Arizona and a member of the Foreign Relations Committee. "But in this instance, we need an Authorization for the Use of Military Force. Our enemies and our allies need to know that we speak with one voice."
In a reflection of how strained relations between the White House and congressional Republicans remain, reaction to the president's proposal in many corners of the Capitol was grudging acceptance.
"You go to war with the president you've got, which would give us all pause," said Senator Mark S. Kirk, Republican of Illinois. Asked whether he had reservations about voting to approve Obama's request, Kirk did not hesitate.
"No," he said. "I think it's the right thing to do to take these guys out."
Administration officials refused to discuss what was in their proposal, saying it would be made public shortly.
With the exception of some more libertarian-leaning lawmakers who will oppose the president because they object in principle to getting involved in another war, Obama's biggest problems may not be with Republicans but with Democrats.
The sharpest debate is likely to focus on the prohibition of "enduring offensive ground operations" and whether that term is so vague it could allow Obama or a future president to launch the kind of ground war so many lawmakers fear.
Because the president would not need to ask Congress for another Islamic State force authorization until 2017, the legislation would cover the next president, as well.