Bush said he would veto the measure. "We reject that idea. It won't work," the president said, speaking to reporters at the Pentagon after a briefing on Iraq and Afghanistan.

The bill being voted on Thursday is opposed by nearly all Republicans and unlikely to survive in the Senate. But House Democratic leaders say the measure shows they refuse to back down in challenging Bush on a deeply unpopular and costly war.

Senate Majority Leader Harry Reid, D-Nev., told reporters he has felt a shift in the administration's approach to Democrats.

"It's very clear that the people around the president recognize there are some problems," said Reid, D-Nev. "And I think I have felt with my conversations with administration officials that there is a right admission that things are not going very well."

Senate Democrats said they anticipate a vote on a war bill by next week, although Reid said it remains unclear what the Senate bill might look like.

"There are 150 scenarios as to how this matter is going to be handled," said Reid. Finding a bill the Congress will pass and the president will sign is "extremely difficult," he added.

Bush pressured Iraqi leaders to move swiftly on a number of long-pending measures, including legislation to share Iraq's oil wealth, hold provincial elections and update the constitution.

"They have got to speed up their clock," the president said. Washington is unhappy that Iraq's parliament plans to take a two-month vacation this summer in the midst of the war.

Bush's willingness to put benchmarks in a war-funding bill represented a shift by the president.

"One message I have heard from people of both parties is that benchmarks make sense and I agree," Bush said. He said his chief of staff, Joshua Bolten, would talk with congressional leaders "to find common ground" on benchmarks.

White House officials decided Bush, after refusing to discuss his negotiating stand, should change course and declare what he is for since he been emphatic about what he is against.

The Democrats' bill in the House would provide the military with $42.8 billion to keep operations going through July, buy equipment and train Iraqi and Afghan security forces. Congress would decide shortly before its August recess whether to release an additional $52.8 billion for war spending through September.

A dozen or so members in Congress are attempting to strike a bipartisan compromise. Few have come forward with concrete plans _ perhaps out of reluctance to champion a proposal until they know it can succeed. None of the proposals put in plain view have picked up steam.

"We'll see what happens," said Rep. Bud Cramer, D-Ala. "A lot of us are coming together across the aisle. We're under the radar now, but we're meeting."

Many Republicans have grown nervous on the war.

Two Republicans _ Reps. Frank Wolf of Virginia and Michael McCaul of Texas _ circulated a letter along with Democrat Mark Udall of Colorado urging their colleagues to co-sponsor legislation that would put in place recommendations from the independent Iraq Study Group.

One of the 79 suggestions from the bipartisan group in December was reducing U.S. "political, military or economic support" for Iraq if the Baghdad government could not make substantial progress toward providing for the country's security. The report suggested an urgent diplomatic attempt to stabilize Iraq and allow the withdrawal of most U.S. combat troops by early 2008.

Bush said Congress should give his buildup of more than 20,000 troops a chance to work.

Gen. David Petraeus, the top U.S. commander, is to report to Bush in September on the effectiveness of the buildup.

"Why don't we wait and see what happens," the president said. "Let's give this plan a chance to work. Let's stop playing politics."

Bush said the House Democrats' plan to pay for the war only through July was "haphazard, piecemeal funding."

Of the five brigades of additional forces being sent to Iraq, Bush said three are already settled there, the fourth has just entered Baghdad and the fifth will arrive in mid-June.

"Al-Qaida is responding with their own surge. Al-Qaida is ratcheting up their own campaign of high-profile attacks," Bush said.

Rep. Tom Davis of Virginia was one of 11 GOP lawmakers who met with Bush and his top aides Tuesday afternoon.

"We asked them what's Plan B," Davis said. "We let them know that the status quo is not acceptable." Davis said the president responded that if he began discussing a new strategy, his current one never would have a chance to succeed.
© 2007 The Associated Press