President Bush ceded some ground in the Iraq War spending debate Thursday, saying he would accept benchmarks in a bill even as the House passed a spending measure that has drawn a veto threat.

Meanwhile, Senate Majority Leader Harry Reid, D-Nev., kept lawmakers in both parties guessing about when he will advance a supplemental spending bill in that chamber.

With their passage of the war emergency spending bill (HR 2206) on a 221-205 vote, House Democrats are seeking to keep the pressure on Bush to begin winding down the U.S. presence in Iraq.

Earlier on Thursday, the House rejected, 171-255, a bill (HR 2237) sponsored by Jim McGovern, D-Mass., that called for withdrawal of U.S. troops from Iraq — with limited exceptions — to start within 90 days of enactment and be completed in 180 days. Defeat of the bill had been expected, but the “aye” votes exceeded supporters’ expectations.

“It’s a huge vote,” Speaker Nancy Pelosi, D-Calif., said outside the House chamber afterward. “I was hoping for 150, so I’m very pleased with the number.”

Later on Thursday, Democrats passed another bill — by a veto-proof 302-120 and with sizable Republican support — that would provide supplemental funding for agriculture disaster relief and combating wildfires (HR 2207). The money was included in the first version of the emergency supplemental bill vetoed May 1; it was not requested by Bush and the measure has separately drawn a veto threat.

There were growing signs Thursday that the pressure on the war that Democrats — as well as some Republicans — seek to impose was being felt in the White House. Bush, after a visit to the Pentagon for a private briefing on the war’s progress, indicated he was prepared to negotiate with Democrats in Congress on setting benchmarks to measure progress in the conflict.

“One message I have heard from people from both parties is that the idea of benchmarks makes sense,” Bush said Thursday after meeting with the Joint Chiefs of Staff. “And I agree. It makes sense to have benchmarks as a part of our discussion on how to go forward. And so I’ve empowered [Joshua B. Bolten, White House chief of staff] to find common ground on benchmarks. And he will continue to have dialogue with both Republicans and Democrats.”

Despite that concession — which did not come as a great surprise, as there has been bipartisan support for benchmarks in Congress — Democratic leaders said benchmarks without consequences would be insufficient.

The first version of the supplemental tied the timetable for troop withdrawal from Iraq to progress benchmarks that the Iraqi government must meet. Many Republicans who have said they would support benchmarks do not want them to be tied to consequences.

“ Benchmarks without consequences and enforcement are meaningless, a blank check,” Pelosi said.

Democrats hope to get a bill to Bush before the Memorial Day recess. But if they are to do so, the Senate must act soon. By holding back on a plan of his own, Reid has given himself maximum flexibility to study the House version of the supplemental and a number of proposals being tossed out by senators in both parties seeking a middle ground on the war.

Sens. Lamar Alexander, R-Tenn., and Ken Salazar, D-Colo., suggested a plan to make the Iraq Study Group’s recommendations the basis for U.S. policy in Iraq.

“We owe it to our country and our troops to find a bipartisan consensus to support where we go from here,” Alexander said. “We need a political solution in Washington, D.C., as much as we need one in Baghdad.”

A bipartisan trio of House members —Democrat Mark Udall of Colorado and Republicans Michael McCaul of Texas and Frank R. Wolf of Virginia — have taken a similar approach. They sent a letter to colleagues May 9 announcing that they planned to try to implement the remaining Iraq Study Group recommendations in future legislation. They expect to introduce a measure after Memorial Day, according to a Udall spokesman.

Sen. John W. Warner, R-Va., said he was preparing to circulate to other senators his plan for incorporating benchmarks into the new supplemental spending bill. Of this proposal, he said, “I think it will be a very simple, understandable framework, showing how to treat benchmarks and what to do.”

Reid noted that separate groups of Democratic senators have been targeting Maine Republicans Olympia J. Snowe and Susan Collins, as well as Alexander, on Iraq, and that Ben Nelson, D-Neb., had been working with Republicans on an exit strategy plan. “Each one of them thinks they have a magic formula,” Reid said.

Minority Whip Trent Lott, R-Miss., said he believes Reid must move a Senate version of the supplemental in coming days.

“I do think this is an issue that is going to begin to backfire on them,” Lott said of congressional Democrats. “If the American people think that Congress’ refusal to work with President Bush on this is hurting the troops, the Democrats have a problem. . . . If all they’re trying to do is pin the partisan tail on the donkey — and the hell with the country and the troops — in the end that will be a loser.”

The House passage of a supplemental war bill that Bush has again vowed to veto showed that Democrats in that chamber are not yet prepared to write a war spending bill without restrictions on the conflict.

Rep. John B. Larson, D-Conn., vice chairman of the Democratic Caucus, said the House is following its own beat on Iraq because members are more attuned to the voters. “You’re out listening to what people have to say,” he said. “They’re not talking about two chambers, they’re not talking about overriding the veto. They’re talking about ‘Bring the troops home.’ ”

In fact, the rule for consideration of the redeployment measure, the Iraq spending bill and the agriculture supplemental provided for combining whichever bills pass individually.

That means that heading into conference, the House will add to the war spending bill the agriculture spending package, which also includes $500 million for combating wildfires, $425 for a county payments program, $60 million for the California salmon industry and $31 million to extend a milk subsidy program for a month.

House Appropriations Chairman David R. Obey, R-Wis., decided to separate the agriculture funding into a second bill following Bush’s veto message on the previous supplemental. Republicans had criticized Democrats for including the extra money to “buy” votes on Iraq, but 80 GOP lawmakers voted for the stand-alone agriculture spending Thursday.

“The president seemed to suggest in his veto message that we didn’t have the courage to deal with the agriculture and other related issues alone, that we had to slip them in, so to speak, in the Iraq bill. And frankly, that got my dander up,” Obey said.

The White House issued statements of administration policy carrying veto threats on both of the spending bills, as well as on the McGovern troop withdrawal measure.

The McGovern bill was never expected to pass, but just holding the vote represented a major victory for members of the Out of Iraq Caucus.

McGovern said the opportunity arose out of a meeting he had May 9 with Pelosi. “I think if it were a secret ballot I think there would be quite a few Republicans who would want to join with me,” he said. “But it’s not a secret ballot and I think a lot of them are afraid of repercussions and so they’re going to continue to toe the line.”

Allowing the vote also was intended to make it easier for some Out of Iraq House members to vote for the war funding bill, as they know that is the most restrictive language they can get.

The measure would provide $42.8 billion in war funds immediately, enough for two to three more months, but would require another vote in late July to release the remaining $52.8 billion to the Pentagon.

The removal of a fixed withdrawal timetable from the funding bill served to pick up the votes of several conservative Democrats who were among the 13 who opposed the original House war funding bill, including John Barrow and Jim Marshall of Georgia, Lincoln Davis of Tennessee, Dan Boren of Oklahoma, Jim Matheson of Utah and Gene Taylor of Mississippi.

Marshall said before the vote that, as he sees it, the spending bill does not have strings attached, and “half a loaf is better than none.”

Taylor agreed that this bill makes more sense. “The other one had hard and fast deadlines,” he said. “This one really strikes me as a fairly reasonable approach. We’re calling on the commander in chief to tell us what the game plan is.”

Republicans mostly stuck together on the Iraq supplemental vote, with only two — Walter B. Jones of North Carolina and Wayne T. Gilchrest of Maryland — voting for it. They were also the only two House GOP lawmakers to vote for the supplemental Bush vetoed.

Jones noted that during the debate earlier this year over the increase, or “surge,” of U.S. troops in Iraq, 10 Republicans had spoken against the surge, with 17 voting to oppose it.

“Of those people, of those 10, I think that if things continue to go the way they are . . . by the end of July six or seven of them will probably make the decision we’ve got to have an end to this war,” Jones said.

About a dozen House moderates met with Bush on May 8, chaperoned by House Minority Leader John A. Boehner, R-Ohio. The meeting was described by a GOP leadership aide as “a venting session” that gave members the opportunity to tell Bush how the war is hurting them in their districts.

“The purpose of the meeting was to talk about where we are, what happens in September, and the way forward,” said Rep. Ray LaHood, R-Ill., who attended. “They are willing to stick with Bush until September, but we want an honest assessment from [Gen. David] Petraeus in September, and then people are going to evaluate where we are.”

Rep. Jack Kingston, R-Ga., said that even if Republicans in swing districts continue to vote against Democratic proposals on Iraq, they will not parrot the president. “They’re going to have to start fishing a different line,” he said. “Rhetorically, you’re going to see a lot more distancing.”

Alan K. Ota, John M. Donnelly, Michael R. Crittenden, Catharine Richert, Susan Ferrechio, Michael Teitelbaum, Jonathan Allen and Martin Kady II contributed to this story.