(From left) Democratic Senators Harry Reid, Chuck Schumer and Joe Biden after Iraq vote

The Senate, by a 50-48 vote, rejected a Republican-sponsored amendment to strip the funding measure of the provision that calls for U.S. troops to start pulling out of Iraq within four months, with a goal of completing withdrawal by March 31 of next year.

The vote came just hours after White House spokeswoman Dana Perino renewed President Bush's vow to veto the bill if it contained the timetable for withdrawal. "The legislation would substitute congressional mandates for the considered judgment of our military commanders. The bill assumes the failure of the new strategy even before American commanders in the field are able to fully implement their plans," she said.

Many Senate Republicans, including Senator John McCain of Arizona, echoed Perino's comments. "If you announce to the enemy that you are leaving, it is a recipe for defeat," he said.

But Senate Majority Leader Harry Reid, a Nevada Democrat, noted that public opinion polls show a majority of Americans favor a timeline to bring the troops home. He said the time had come to send the president a message. "This is a civil war. It has turned into an intractable civil war. The president must change course, and this legislation will allow him to do that," he said.

It is the first time the Senate has signaled its support for a timetable for a troop withdrawal from Iraq, having rejected the idea several times this year.

Senator Chuck Hagel, a Nebraska Republican, was among those who rejected a resolution calling for a timeline for a troop pullout just two weeks ago, only to back the idea now. "America finds itself in a dangerous and isolated position in the world. We are perceived as a nation at war with Muslims. This debilitating and dangerous perception must be reversed as the world seeks a new center of gravity for this new century. The United States must begin planning for a phased troop withdrawal from Iraq. The cost of combat in Iraq in terms of lives, dollars and world standing has been devastating for our country," he said.

The House of Representatives last week passed its own version of the spending bill for the military missions in Iraq and Afghanistan, including a deadline for withdrawing U.S. troops from Iraq by August 31 of next year.

Once the Senate approves the overall legislation, a move that could come as early as Wednesday, the measure will have to be reconciled with the House bill before it is sent to President Bush for his expected veto.

The House and Senate would then have to redraft the legislation, as they would lack the two-thirds majorities needed to override the veto.

The overall bill includes 96 billion dollars to continue funding the military missions in Iraq and Afghanistan. It also includes money to strengthen port and mass transit security.

The Pentagon says it needs the funding soon, as money for its operations in Iraq and Afghanistan will run out next month.