Senate Democratic leaders scored a major victory Tuesday as members rejected, 48-50, a Republican attempt to strip U.S. troop-withdrawal language from an Iraq War spending bill.

Republicans Gordon H. Smith of Oregon and Chuck Hagel of Nebraska joined with most Democrats to reject the amendment, by Thad Cochran, R-Miss. Mark Pryor of Arkansas was the only Democrat to vote for the amendment. Independent Joseph I. Lieberman of Connecticut, who caucuses with the Democrats, also supported it.

With Republicans signaling that a filibuster is unlikely, the vote strengthens the Democrats’ hand heading into conference and makes it a virtual given that the conference report will contain troop-withdrawal provisions, setting up a nearly certain veto from President Bush.

The $121.7 billion Senate legislation would set a goal of withdrawing most U.S. troops from Iraq by a year from now. The $124.3 billion House version of the bill, which passed, 218-212, on March 23, includes a timetable that calls for troop withdrawal by the end of August 2008, at the latest, and requirements for troop readiness, which Bush could waive.

Hours before the Senate vote, the White House unequivocally warned that Bush would veto the Senate version of the bill (HR 1591), which would fund military operations in Iraq and Afghanistan through fiscal 2007. The administration, which issued a similar threat when the House voted, objects to the troop-withdrawal provision, as well as spending for purposes unrelated to the war.

“Congress should reject this legislation and promptly send the president a responsible bill that provides the funding and flexibility our troops need, without holding funding for the troops hostage to unrelated spending,” the White House said in a statement.

After the vote on his amendment, Cochran acknowledged, “The president probably will have to veto the bill now.”

Democrats hoped the vote would put some political heat on Bush.

“The American people have asked us to give our troops an effective, successful strategy for victory in Iraq. Both houses of Congress have listened. It is now up to the president to do the same,” said Senate Majority Leader Harry Reid, D-Nev.

The Senate began debating the bill Monday, and Democratic leaders are hoping for a vote on passage as early as Wednesday. Republicans have criticized the provision that calls for starting a withdrawal of U.S. troops from Iraq, with the goal of finishing by the end of March 2008.

Earlier this month, the Senate rejected a nearly identical withdrawal measure (S J Res 9) by Reid, on a 48-50 vote. Hagel and Ben Nelson, D-Neb., voted against that measure, but switched their votes Tuesday.

Vice President Dick Cheney came to the Hill in case his vote was needed to break a 49-49 tie. Tim Johnson, D-S.D., who is recovering from a brain hemorrhage, is not voting. Michael B. Enzi, R-Wyo., who would have supported the amendment, was in Wyoming because his mother was ill, according to a spokesman.

Nelson had said the Cochran amendment struck some language that he felt should have been retained, saying U.S. troops should not be policing a civil war.

Nelson had also agreed to support the supplemental after negotiating with Reid and winning the inclusion of progress benchmarks for the Iraqi government and reporting requirements for the commander of the coalition forces. “When they put the benchmarks in, the game changed,” he said after the vote.

Pryor said he supported the amendment because he believes it is a mistake to publicly announce strategic timetables.

“That is why I support a plan that would force the administration to create a classified campaign plan for Iraq, including strategic and operational benchmarks and classified redeployment dates,” he said in a statement.

Some Republicans who supported Cochran’s amendment nonetheless expressed reservations about the war.

“This doesn’t mean that I support an unending commitment of our troops,” said Republican Susan Collins of Maine.

Senate Minority Leader Mitch McConnell, R-Ky., has indicated that Republicans likely would not filibuster the bill in the interest of getting it more quickly to Bush for his inevitable veto.

Before the vote, McConnell said, “My suspicion is that regardless of the outcome of the Cochran amendment . . . the Senate might recede to the House in conference, thereby making veto a certainty, and we’d have to go through this process all over again. So my goal is to get through the process as quickly as possible, because we may have to go through it all over again.”

Charles E. Schumer, D-N.Y., acknowledged the likelihood of a veto but likened the vote to “not one battle; it’s a long-term campaign to persuade the president, to pressure the president to change course.”

“Every time we have a vote like this, it ratchets up the pressure on the president and on many of those of his party who are caught between his desire to stay with the same policy in Iraq and the American people’s common-sense, deep, deep knowledge that we have to change course,” Schumer said.

Republicans — particularly fiscal conservatives — have chastised Democrats for including billions of dollars for unrelated domestic items, such as aid for spinach and dairy farmers.

John McCain, R-Ariz., said he and others were working on amendments to strike some of the extra spending. “It’s disgraceful. It’s bribery,” McCain said.

The Senate bill includes close to $20 billion more than Bush’s $103 billion request.

The Senate also is expected to adopt an amendment to raise the minimum wage by $2.10 an hour. Senate Finance Chairman Max Baucus, D-Mont., said it will be coupled with a package of small-business tax breaks, totaling $8.3 billion, that the Senate passed Feb. 1.

Minority Whip Trent Lott, R-Miss., who has been highly critical of the additional spending, said he supported attaching the wage and tax breaks package to the supplemental.

“This is strictly just a tactical move to make sure the Senate position is the same,” he said.

The House version of the supplemental also includes a minimum wage increase and a narrower package of tax breaks, totaling at least $1.3 billion.

Jonathan Allen, Daphne Retter, Tim Starks and Libby George contributed to this story.

First posted March 27, 2007 12:04 p.m.