Bipartisan negotiations on the Iraq spending bill began in earnest on Friday, with both sides expressing initial disappointment but still pledging to work to reach a deal by Memorial Day.

The Kabuki dance began with little movement, as Democrats offered two proposals with concessions that already had been rejected by the White House, and the administration offered a deal that already had been dismissed by Democrats.

Democrats first proposed eliminating all of the domestic spending in the bill for Hurricane Katrina, agriculture relief and other programs if the president would agree to timelines for withdrawal from Iraq. They then offered to cut some of the domestic spending and allow the president to waive the withdrawal timelines.

Both ideas were declared dead-on-arrival by White House Chief of Staff Josh Bolten, who said timelines for withdrawal would not be supported by the president in any form, whether or not they included waivers.

“We consider that to be not a significant distinction,” Bolten said. “Whether waivable or not, timelines send exactly the wrong signal to our adversaries, to our allies and, most importantly, to the troops in the field.”

Bolten instead floated the proposal by Sen. John Warner (R-Va.) for tying benchmarks for the Iraqi government to potential loss of reconstruction aid.

“I think Republicans are in most respects united around an approach that Sen. Warner was able to pull together — again on a bipartisan basis — that involves using benchmarks on the Iraqis, having accountability for those benchmarks and giving the president the obligation to come back and report to the Congress,” Bolten said.

Warner’s idea had garnered 52 votes in the Senate, including 44 Republicans, earlier in the week, but has been blasted by Senate Majority Leader Harry Reid (D-Nev.) as “nothing” in part because Bush could choose to block any consequences for the Iraqis.

The administration also offered to accept some of the additional security-related spending Democrats added to the bill, but Democrats said the administration had given little.

“To say I was disappointed in the meeting is an understatement,” Reid said. “The American people want our troops to come home. The American people expect the president to respond.”

“It is clear that the difference between the Democrats and the president is the issue of accountability,” added Speaker Nancy Pelosi (D-Calif.). “He will not accept any accountability or responsibility for what is happening.”

Nonetheless, Reid said staff will work over the weekend and he expects to have a bill today. If they can’t reach a deal, leaders have made it clear that they are prepared to work through the Memorial Day recess.

Democrats and Republicans privately expect that a troop-funding bill combined with beefed-up benchmark accountability for the Iraqi government will emerge in the coming week. But Democrats are not willing to withhold funding for the war indefinitely and don’t have the votes to override the president.

Any such deal will essentially postpone until September the next major Iraq decision point.

Or, as Rep. Mike Simpson (R-Idaho) says, “Then all hell breaks loose.”

Several Republicans say they will not continue voting for the war if significant progress is not made this summer.

“You won’t find many Republicans willing to support Americans shedding their blood if the Iraqi government goes on vacation for two months,” Simpson said. If the situation does not improve, “you will probably see major efforts by Republicans and probably successful efforts to pull out.”

Members are feeling pressure back home, with polls consistently showing most Americans opposing Bush’s handling of the war.

“The patience of the country is very, very thin right now,” said Rep. Ray LaHood (R-Ill.), adding that “a lot of progress has to be made” before September to keep GOP support.

Rep. Jim Walsh (R-N.Y.), one of 17 Republicans to vote against Bush’s troop “surge” policy, said he hopes Republicans can successfully pressure Bush to change course in Iraq if the situation does not improve by September. If not, “I think there would be a number of Republicans willing to look at Plan B.”

Advocates on both sides of the issue also released new polling data. A poll by Greenberg Quinlan Rosner Research Inc. released by Americans Against Escalation in Iraq found increasing opposition to the war in 50 battleground districts across the country, including 19 seats held by Republicans. Two-thirds of the voters in the Republican-held suburban districts opposed continued funding without strings attached.

But the Republican National Committee looked for the bright side in polling data it released. “We show the increase in people who feel the war is going badly has stopped,” the RNC said in a memo released Friday. “Although a majority of the public continues to feel the war is going badly, we have seen a small increase throughout the spring in the number of people who feel things are going better in Iraq.”

Jennifer Yachnin contributed to this report.