Republicans blocked a full-fledged US Senate debate over Iraq on Monday, but Democrats vowed to find a way to force President George W. Bush to change course in a war that has claimed the lives of more than 3,000 US troops and tens of thousands of Iraqis. "We must heed the results of the November elections and the wishes of the American people," said Harry Reid, leader of the Democratic majority. Reid spoke moments before a vote that sidetracked a nonbinding measure that would express disagreement with Bush's plan to deploy an additional 21,500 troops to Iraq. The political jockeying unfolded as Democrats sought passage of a nonbinding measure, supported by Republican Sen. John Warner, that was critical of the administration's new Iraq policy. It is the first time Democrats scheduled a sustained debate on the war since they won control over Congress in last fall's congressional elections.