Senate Republicans defeated a Democratic resolution calling for redeployment and eventual withdrawal of U.S. troops from Iraq, language that could soon resurface during debate on the war supplemental funding bill.

By a vote of 48-50, senators on Thursday voted down a binding resolution (S J Res 9), sponsored by Majority Leader Harry Reid, D-Nev., that would have begun scaling back the Iraq mission within four months of its adoption. It also would have set a goal — but not a requirement — that combat troops be pulled out by March 31, 2008. Under terms of the debate, 60 votes were required for adoption.

The Senate instead voted overwhelmingly in favor of two non-binding, more benign resolutions that essentially said the Senate supports U.S. troops.

Democrats and Republicans accused each other of being on a dangerous path that could end in ruin.

“Giving notice [of withdrawal] to the other side is a guarantee of defeat in Iraq and a guarantee that we’ll have these problems back in the homeland,” said Minority Leader Mitch McConnell, R-Ky. “It is exactly the wrong way to go.”

Democrats said the troops’ mission should be limited to counterterrorism, training Iraqi forces and protecting U.S. assets.

“The idea of policing a civil war is something we don’t need to be doing anymore,” said Charles E. Schumer, D-N.Y. “Republican senators are caught. . . . They’re caught between a president who sticks to these policies and a constituency that knows this policy is wrong.”

Democrats knew Reid’s controversial resolution had little chance of succeeding. The vote was an attempt to put pressure on Republicans to support limits on the Iraq War, or face the prospect that a “no” vote could come back to haunt them during the 2008 elections. It was not the first time, and it will not be the last, Democrats said.

Anti-war voters, who helped give Democrats a congressional majority last November, are eager to see results. But the razor-thin Democratic margin in the Senate makes it difficult for them to push aggressive measures that can overcome a filibuster.

The carefully constructed Reid resolution was the result of a compromise between caucus liberals who wanted to set a withdrawal date and conservatives who wanted it to be a goal so it would give the president flexibility.

Meanwhile, Republicans are torn between supporting President Bush and voter dissatisfaction with the war, which will make them vulnerable to Democratic pressure.

Democrats have few options now but to squeeze Republicans until their support for the war erodes or until voters topple more GOP members next year. Gordon H. Smith of Oregon, who is near the top of Democrats’ list of senators to defeat in 2008, was the only Republican to back the Democratic resolution.

On the other hand, one red-state Democrat up for re-election in 2008, Mark Pryor of Arkansas, voted against it. Nebraska Democrat Ben Nelson, up for re-election in 2012, joined him.

Republicans had blocked the Iraq debate before, angry that their alternative proposals would not be considered under the terms they sought. But after Democrats painted them as obstructionists, Republicans decided they could argue successfully that Democrats were endangering national security and endorsing retreat.

This time, Democrats allowed a vote on the one resolution Republicans wanted: a non-binding measure (S Con Res 20) sponsored by New Hampshire Republican Judd Gregg, stating the Senate’s commitment to not taking away funding for troops. It represented GOP efforts to put pressure on Democrats not to use appropriations power to limit or end the war, a path favored by some party liberals.

Despite Democratic leaders’ attempts to dissuade their caucus from voting for the Gregg resolution, it was adopted, 82-16.

Prior to that vote, the Senate adopted, 96-2, a Democratic resolution touted as an improvement to Gregg’s measure. Sponsored by Patty Murray of Washington, it would express support for funding troops in the field and for medical care after they return from combat — a reference to the furor over the care some veterans received at Walter Reed Army Medical Center.

The Gregg and Murray resolutions also differ in their introductory sections. The Gregg resolution states that, under the Constitution, the president has “the authority to deploy troops and direct military campaigns during wartime.” The Murray resolution states that the Constitution gives Congress and the president “shared responsibilities for decisions on the use of the armed forces of the United States, including their mission.”

Murray said the Gregg resolution would turn Congress into “an ATM for the president’s war plan.” McConnell dismissed the Murray resolution as an attempt to give Democrats political cover to vote against the Gregg resolution.

The agreement on the Gregg resolution early Thursday opened the door to the first full debate on Iraq in the Democratic-controlled Senate.

McConnell said Democrats could have gotten the same agreement last month during negotiations over a resolution (S Con Res 7), sponsored by John W. Warner, R-Va., that criticized President Bush’s Iraq troop buildup. Democrats at the time called the Gregg resolution a “distraction” and refused to allow its consideration under the 60-vote threshold Republicans sought for the Gregg and Warner measures. That prompted Republicans to block the overall debate.

McConnell said Reid told him the redeployment and withdrawal language would return as part of the fiscal 2007 supplemental appropriations measure, which Senate appropriators will take up March 22. The House Appropriations Committee approved a supplemental spending plan Thursday that includes a timetable for withdrawal from Iraq.

Reid has said only that it is possible his resolution’s language could be attached to the supplemental. But he characterized the resolution as part of a “process” to confront the president and Senate Republicans on war policy.

Republicans would not say whether they would block the supplemental if it included Reid’s language. The White House has already threatened a veto. “If it’s a must-pass bill, it certainly shouldn’t be junked up with language like this,” McConnell said.

Kay Bailey Hutchison of Texas, an appropriator and chairwoman of the Republican Policy Committee, raised the possibility of a bridge funding bill, should redeployment language bog down debate on the supplemental.