Several Republican senators Tuesday called for President Bush to implement a new war strategy based on recommendations by the Iraq Study Group, which advocated winding down the U.S. combat mission.

"The president needs bipartisan support if the United States is to sustain a long-term position in Iraq," said Sen. Lamar Alexander, R-Tenn.

The message that must be sent to the president is, "Let's see if we can agree on an entire approach so you can have the kind of support you need," he said.

Alexander and Sen. Ken Salazar, D-Colo., introduced legislation that would make most of the study group's 79 recommendations official U.S. policy. At least six other senators, including three Republicans, signed on as co-sponsors.

The proposal indicates mounting frustration in Congress with the politically unpopular war as lawmakers head into the 2008 elections.

The study group released its recommendations six months ago, only to receive a tepid response from the White House and Congress alike. Now, several new Republicans have stepped forward to endorse it, including two Bush loyalists close to GOP leadership, Sens. Robert Bennett of Utah and Judd Gregg of New Hampshire.

"What we have here, hopefully, is a roadmap for consensus," said Gregg. "That's what we need."

Bennett called the proposal "a nudge" for the president.

The issue of Republican support for such a bill is crucial, particularly in the Senate, where Democrats hold a razor-thin majority and lack enough support to overcome a presidential veto.

An identical bill in the House was introduced by Democratic Reps. Mark Udall of Colorado and Daniel Lipinski of Illinois, and GOP Reps. Frank Wolf of Virginia and Michael McCaul of Texas. That bill had more than 40 other co-sponsors, including some 22 Republicans.

The blue-ribbon study group — co-chaired by Republican James Baker and Democrat Lee Hamilton — said U.S. troops' primary mission should evolve to supporting Iraqi security forces. The group also said the U.S. should reduce political, military or economic support for Iraq if the government in Baghdad cannot make substantial progress.

If certain steps were taken, most troops could come home by early 2008 and a smaller contingent of forces could stay to support the Iraqis and strike al-Qaida targets, the panel said.

Hamilton said in a phone interview last week that he was not surprised by the recent warming in Washington to the study group's recommendations.

"If you're going to get out of Iraq, you have to make the primary mission training the Iraqis," he said.

Ryan Crocker, U.S. Ambassador to Iraq, said Tuesday he does not see an "end game" in sight to the struggle in Iraq.

"I think that in the U.S., we're looking at Iraq right now as though it were the last half of a three-reel movie," he told NPR News' "Morning Edition" in an interview to be aired Wednesday. "I think for Iraqis, it's a five-reel movie and they are still in the first half of it."

At a May 24 news conference, Bush told reporters he would "like to see us in a different configuration at some point in time in Iraq" once Baghdad is brought under control. He also said that recommendations from the bipartisan Iraq Study Group "appeal to me."

Privately, Bush has told lawmakers he is open to the group's recommendations but wants to consider them on his own time and does not want to be forced by Congress.

So far, GOP leadership has backed him on this point. Senate GOP leader Mitch McConnell told reporters Tuesday he was aware of members' growing support for the Iraq Study Group's findings, but that Congress should not intervene.

After a critical review of progress this September, "I anticipate that we'll probably be going in a different direction in some way in Iraq," said McConnell, R-Ky. "And it'll be interesting to see what the administration chooses to do."

But Bush's insistence that he decide when to take the next step in Iraq is unlikely to sit well with many Republicans. According to GOP aides, the goal for many members is to step out ahead of Bush in calling for change and prove to voters they are not in lockstep with his politically unpopular policies. They also want to ensure combat missions wind down by next spring, as members head into the 2008 elections.

"The problem for many Republicans is that following the president on his own timetable might not be quick enough or provide enough distance with a president" whose war policies are unpopular, said one Senate Republican aide, who requested anonymity because of the sensitivity of the subject.

Sen. Susan Collins, R-Maine, said she wanted to join the list of co-sponsors for the proposal, while Sen. Olympia Snowe, R-Maine, said she was open to the idea. Collins and Snowe have signed on to previous proposals in opposition to Bush's troop buildup in Iraq.

"It seems to me the surge (in forces) is not working as well as we hoped" and it would be "helpful to shine a spotlight" on a new approach, said Collins.