WASHINGTON – Republicans blocked a full-fledged Senate debate over Iraq yesterday, but Democrats vowed they still would find a way to force President Bush to change course in a war that has claimed the lives of more than 3,000 U.S. troops.

“We must heed the results of the November elections and the wishes of the American people,” said Majority Leader Harry Reid.

Reid, D-Nev., spoke moments before a vote that sidetracked a nonbinding measure expressing disagreement with Bush’s plan to deploy an additional 21,500 troops to Iraq.

The vote was 49-47, or 11 short of the 60 needed to go ahead with debate, and left the fate of the measure uncertain.

Senate Republican Leader Mitch McConnell of Kentucky described the test vote as merely a “bump in the road” and added that GOP lawmakers “welcome the debate and are happy to have it.”

The political jockeying unfolded as Democrats sought passage of a measure, supported by Sen. John Warner, R-Va., that is critical of the administration’s new Iraq policy.

It was the first time Democrats had scheduled a sustained debate on the war since they won control over Congress in last fall’s midterm elections.

McConnell called for equal treatment for an alternative measure, backed by Sen. Judd Gregg, R-N.H., saying Congress should neither cut nor eliminate funding for troops in the field. That measure takes no position on the war or the president’s decision to deploy additional forces.

Democrats launched a withering attack on Bush’s war policy in the run-up to the vote.

“The American people do not support escalation. Last November, voters made it clear they want a change of course, not more of the same,” Reid said. “The president must hear from Congress, so he knows he stands in the wrong place, alone.”

Sen. Dick Durbin of Illinois, the second-ranking Democrat, echoed Reid. “If the Republicans want to stand by their president and his policy, they shouldn’t run from this debate. If they believe we should send thousands of our young soldiers into the maws of this wretched civil war, they should at least have the courage to stand and defend their position,” he said.

The war has claimed the lives of more than 3,000 U.S. military personnel so far, and costs are counted in the hundreds of billions of dollars. The administration in recent days asked Congress for $245 billion more to cover the costs of the conflict through 2008.

Before the test vote, McConnell sought to deflect charges that Republicans were hoping to block a debate. He said the roll call was meaningless, a “bump in the road” required to settle a procedural problem.