WASHINGTON -- Congress split yesterday over establishing a firm deadline for removing American troops from Iraq, with a closely divided Senate defeating a withdrawal timetable and a House panel calling for a redeployment to begin within one year.

The Senate voted 50-48 against a resolution requiring all but essential support troops to leave Iraq by March 2008.

It was a largely partisan vote. Only one Republican, Sen. Gordon Smith of Oregon, broke ranks to join 47 Democrats, while two Democrats -- Sens. Mark Pryor of Arkansas and Ben Nelson of Nebraska -- and one Independent, Joe Lieberman of Connecticut, sided with the Republicans.

"It's very clear. The Republicans are rubber-stamping the president's failed policies," said Senate Majority Leader Harry Reid, D-Nev., the measure's lead sponsor.

Yet yesterday was a significant victory for Republicans, who had relied on parliamentary maneuvers for weeks to delay an extensive debate on Iraq. They changed course in recent days, allowing Mr. Reid's proposal to advance and demonstrating that Democrats were unable to muster enough support in Congress to push through sweeping changes in Iraq policy, despite the party's victory in the November election.

"I think this is a good day," said Sen. Trent Lott, R-Miss. "The Senate had the debate, had the votes and took a courageous stand."

Sen. Bob Casey, D-Pa., and Sen. Arlen Specter, R-Pa., stayed with their parties. Mr. Specter decried efforts to "micromanage" the war, arguing that lawmakers should wait for a fuller assessment of how a new Baghdad security operation is working.

Senate Republican leaders warned Democratic colleagues not to attach a withdrawal deadline to President Bush's request for nearly $100 billion in extra money for the fighting in Iraq and Afghanistan.

House Democrats have already taken that approach, and, yesterday, that chamber's Appropriations Committee approved an emergency spending bill that would pull combat troops from Iraq by the fall of 2008.

Rep. John Murtha, D-Pa., a Vietnam veteran and the House's highest-ranking member on military spending, spoke passionately at the committee hearing, his voice rising with anger as he recounted the Iraq war's burden on the volunteer military.

"Our strategic position in the world is in jeopardy," the Johnstown Democrat almost shouted, emphasizing each word.

He berated his colleagues for talking about the war as a national struggle when few Americans serve in the military.

"We're not fighting this war on terror from the floor of the House," he said. "We're on an air-conditioned floor, going back to our offices, going back to our homes and going about our business. They're fighting. A very small segment of this country is fighting this war on terror."

Mr. Murtha and other top House Democrats have added more than $21 billion to the president's request, including an extra $1.7 billion for veterans' health care, $2.3 billion for an increase in the size of the military and $1 billion for Afghanistan, which Democrats describe as the central front in the war on terrorism.

There is also $2.5 billion for the "strategic reserve readiness fund," addressing one of Mr. Murtha's main concerns. Lengthy tours overseas for soldiers have drained equipment and training time for stateside military units. The supplemental spending bill calls for troops to receive more training, better equipment and at least one year of rest between deployments. But Mr. Bush can request waivers for those requirements.

The bill also says troop withdrawals will begin before next year if Iraqis do not start meeting political benchmarks and curbing sectarian violence. The first deadline is this summer.

House Republicans said Democrats were vastly overstepping congressional power. "We should not set the timetables. We should not determine the troop movements. We should not try to micromanage the battles," said Rep. C.W. Bill Young, R-Fla.

Rep. Jerry Lewis, R-Calif., the ranking Republican on the Appropriations Committee, accused Democrats of trying to win votes by attaching billions of dollars for programs unrelated to the war, including $735 million for health insurance for children and $400 million for the Low Income Home Energy Assistance Program, or LIHEAP.

Indeed, House Democrats have worked hard to bring together a fractured caucus. Some liberal members are calling for an immediate end to the war, while conservative and moderate Democrats appear uneasy about placing heavy restrictions on the president's use of military force.

Only one prominent liberal Democrat, Barbara Lee of California, voted against the spending bill during yesterday's committee hearing, suggesting the party may be able to unite next week when the full House votes.

But even if the spending bill passes, it appears unlikely to succeed in the Senate. And Mr. Bush has promised to use his veto power.