The Senate’s Democratic presidential candidates are signaling that efforts by their party’s leaders to forge consensus on an Iraq war policy will grow increasingly difficult as the primary season moves into full swing.

Yet some of the candidates appeared to leave the door slightly open to compromise measures, a dynamic that could provide fresh fodder along the campaign trail.

The legislative maneuvering came on the second day of congressional testimony by Gen. David Petraeus, the top American commander in Iraq, and by the U.S. ambassador to Iraq, Ryan Crocker. Both appeared on Tuesday before two panels on which the Senate’s four Democratic White House hopefuls sit. During the hearings, the candidates and senior Democrats were united in their skepticism of the claims by the senior U.S. officials that President Bush’s troop surge was reaping military progress, and they were equally critical of calls to maintain next year the number of troops at their pre-surge level of about 130,000.

Behind the scenes, however, lawmakers say that finalizing a new legislative strategy remains elusive. In particular, they point to the difficulty in holding together Democrats who are running for president and the liberals in the caucus. Defections will make it difficult to reach the 60-vote threshold in a narrowly divided Senate, where most Republicans still oppose any policy that would restrict Bush’s conduct of the war.

“I think it’s a challenge to get 60 votes to agree on what day it is in this environment,” said Sen. Ben Nelson, the conservative Democrat from Nebraska, who has drafted a proposal with vulnerable Maine Republican Susan Collins to change the mission in Iraq without setting a firm deadline for withdrawal. “The presidential politics are pretty clear, and they’re going to have different ideas about what to do.”

Recognizing they lack the votes on a signature proposal to bring troops home by next April, Democratic leaders are considering watering that plan down in the hopes of winning enough Republican support to force President Bush’s hand on Iraq. The measure would revise a Democratic amendment written by Sens. Carl Levin (D-Mich.) and Jack Reed (D-R.I.) from insisting on a hard deadline for withdrawal by next April to calling for a goal of cutting down troop levels.

“There will undoubtedly be proposals to reduce troop levels below General Petraeus’ proposals,” said Senate Majority Whip Dick Durbin (D-Ill.). “At this point, we haven’t agreed on the exact strategy.”

As they work to win over Republicans, Democratic leaders may be losing their colleagues, including the four running for president.

Democratic presidential candidate Sen. Chris Dodd of Connecticut has so far been the most vocal in attacking talk of a compromise measure. His campaign issued an attack on Tuesday against Sen. Barack Obama (D-Ill.), questioning whether he would support a less restrictive measure.

“While we are glad that Senator Obama has called for a change of course in Iraq, he isn’t clear as to what he will do to make that happen, or when,” said Dodd communications director Hari Sevugan. “Rhetoric and highly nuanced statements are not going to end this war — strong leadership and clarity are.”

The Dodd campaign was responding to Obama’s statement that he “can only support a policy that begins an immediate removal of our troops from Iraq’s civil war, and initiates a sustained drawdown of our military presence.” He did not specifically say whether he would only vote for a plan that includes an end date for withdrawing troops.

The Obama campaign did not respond directly to Dodd, but a spokeswoman said the Illinois Democrat would lay out his plan for ending the war in a Wednesday speech in Iowa.

“Senator Obama is proud to have a record [of] opposing the war in Iraq from the start,” said spokeswoman Jen Psaki, issuing a subtle jab at Democratic front-runner Sen. Hillary Rodham Clinton (N.Y.), who voted for the measure authorizing the war in 2002.

Clinton issued a statement last week saying she supported measures to “begin to withdraw our troops and to complete the redeployment of combat troops in 2008,” but she has not said whether she would oppose a measure that does not include an end date.  Another Democratic candidate, Sen. Joseph Biden (D-Del.), also has called for troops to be withdrawn and floated a proposal dividing up Iraq’s warring ethnic factions under a decentralized federal government. He did not say on Tuesday whether he would oppose a compromise withdrawal measure.

“We’re still talking about 1,000 — over 1,000 — weekly
attacks … And we’re calling that success,” Biden, the Foreign Relations Committee chairman, lamented to Petraeus.

But Petraeus found supporters in Republicans such as Sen. Lindsey Graham (R-S.C.), who said Tuesday’s hearings turned into a White House tryout.

“I think there are a lot of people auditioning for commander in chief right now, based on whether or not we should withdraw or reinforce our success,” Graham told The Hill outside the hearing room.

Graham is a strong backer of Sen. John McCain (Ariz.), who was the sole Republican running for the White House to ask questions. McCain, the ranking member of the Armed Services Committee, is highly supportive of the troop surge, and Graham believes this view could pay dividends next year.

“Everybody thinks that ’08 is going to be a terrible political year for Republicans because of Iraq,” he said. “My belief is that the statements you are making now about what to do in Iraq will be looked at in ’08 in terms of whether or not you are ready to be commander in chief.”

Graham added that the evidence shows that the surge has been successful and that candidates who simply want to withdraw troops now without thinking about the consequences do not deserve to be president.

In the House, meanwhile, the legislative outlook is no clearer.

Speaker Nancy Pelosi (D-Calif.) said after a Tuesday meeting with congressional leaders and Bush that the president’s decision to send 30,000 additional soldiers to Iraq has committed the U.S. to a “10-year, high level presence.” House Democratic leaders reconvened Tuesday in Pelosi’s office after the meeting at the White House to plot a way forward in Iraq. No consensus has emerged on what legislative steps to take after this week, according to Majority Leader Steny Hoyer (D-Md). But he said he hoped there was “movement toward consensus.”
    
Elana Schor, Klaus Marre and Jonathan E. Kaplan contributed to this story.