The vote was a loss for Sen. Russell Feingold, D-Wis., and other Democrats who want to end the war. But the effort picked up support from members, including presidential hopefuls previously reluctant to limit war funding — an indication of the conflict's unpopularity among voters.
The proposal lost 29-67 on a procedural vote, falling 31 votes short of the necessary votes to advance.
Sen. Hillary Rodham Clinton, a Democratic presidential front-runner, previously opposed setting a deadline on the war. But she said she agreed to back the measure "because we, as a united party, must work together with clarity of purpose and mission to begin bringing our troops home and end this war."
Sen. Barack Obama, another leading 2008 prospect, said he would prefer a plan that offers more flexibility but wanted "to send a strong statement to the Iraqi government, the president and my Republican colleagues that it's long past time to change course."
The proposal had been expected to fall short of the 60 votes needed to advance under Senate rules, but was intended to gauge the tolerance of members on anti-war legislation. Senate Majority Leader Harry Reid staged a series of war votes Wednesday to inform negotiations with the House on a war spending bill.
"We stand united.... in our belief that troops are enmeshed in an intractable civil war," said Reid, D-Nev.
Feingold's measure, co-sponsored by Reid and Sen. Christopher Dodd, D-Conn., proved divisive for Democrats.
Sen. Carl Levin, chairman of the Armed Services Committee, said he opposes any measure that cuts off money for the war.
"We don't want to send the message to the troops" that Congress does not support them, said Levin, D-Mich. "We're going to support those troops."
But other Democrats said the move was necessary.
"I'm not crazy about the language in the Feingold amendment, but I am crazy about the idea that we have to keep the pressure on," said Sen. Joseph Biden, D-Del., who also wants the Democratic presidential nomination.
The Senate vote on Feingold's legislation was one of several expected Wednesday, as the Democratic-controlled Congress struggles to clear legislation for Mr. Bush's signature by the end of next week to continue U.S. military operations through Sept. 30.
The House last week passed legislation funding the war on two separate, 60-day installments.
The Senate must take the next step by passing its own measure. Given the political forces at work, that legislation will be a placeholder, its only purpose to trigger three-way negotiations involving the House, Senate and Bush administration on a final compromise.
As a result, officials said Tuesday that Reid and Senate Republican leader Mitch McConnell had discussed jointly advancing a bill so barebones that it would contain no funds and do little more than express congressional support for the troops.
Negotiations on the final compromise are expected to take days.
Wednesday's votes on Feingold and other proposals "will provide strong guidance to our conferees and help shape the conference negotiations we have ahead of us," said Reid.
In addition to Feingold's measure, members were expected to vote on legislation by Sen. John Warner, R-Va., that would threaten billions of dollars in U.S. aid for Iraq if Baghdad does not make progress on certain military and political reforms.
Reid said he would oppose Warner's measure because it doesn't go far enough; the proposal would allow the president to waive the restriction on foreign aid.
"It is nothing," said Reid.
Levin pulled from the floor his proposal to set an Oct. 1 date to begin troop withdrawals, but allow the president to waive that requirement. He had pitched the idea with the expectation that the president would accept it because of the waiver; but, Levin said Wednesday he had been advised by the White House that the president would veto the measure regardless.