WASHINGTON — Members are leaning toward scrapping the White House's Islamic State war authorization proposal and starting from scratch, says one senior House Republican.

House Armed Services Committee Chairman Rep. Mac Thornberry, R-Texas, told reporters this week that "not a lot of people … think the president's proposal makes much sense."

But many lawmakers in both parties want a new authorization for the use of military force (AUMF). House Speaker Rep. John Boehner, R-Ohio, has said he wants to put one on the floor for a vote this spring.

So lawmakers are "asking is there a proposal that could pass," Thornberry said. "Members are turning their minds toward that."

The House Foreign Affairs Committee and Senate Foreign Relations Committee have jurisdiction over war authorizations. The latter's last session approved an Islamic State AUMF, but it never reached the chamber floor.

Senate Armed Services Committee Chairman Sen. John McCain, R-Ariz., has said his panel should play a big role in amending the White House draft or crafting a new measure, given the US military's role in fighting the violent Sunni group.

Thornberry acknowledged that Foreign Affairs will lead any House AUMF effort. But he said his committee is "going to play a significant role" because "the military has to live with whatever" limitations and other provisions are included.

The White House last month sent Congress a draft authorization for the use of military force (AUMF) for the ongoing Islamic State conflict. Among other things, it restricts what US military ground forces can do and limits the legal basis for the ongoing conflict to three years.

There is ample confusion among Republican and Democratic members about five key words in the White House's draft: "enduring offensive ground combat operations."

In testimony before congressional panels, Obama administration officials have offered differing definitions of the kinds of missions that would meet the "enduring offensive" threshold, leaving lawmakers confused and frustrated.

Many Republicans believe the White House's proposal is too limiting for the military and future commanders in chief. Democrats believe it is too vague, opening the door for a large-scale US military operation in Iraq — and possibly beyond.