WASHINGTON -- House Democrats threatened yesterday to take up a resolution next week to oppose President Bush's troop buildup in Iraq, cranking up the pressure on Republicans who have blocked a vote on the measure in the Senate.
The move would shift the focus of the debate over the nearly four-year-old war to the House, where Democrats have enough votes to pass a measure over Republican opposition. It may also further isolate the White House and its allies in the Senate, who are bucking public opinion that has turned sharply against the Iraq war and the president's plans to expand it.
Democrats pressured Bush to change course as Defense Secretary Robert M. Gates told lawmakers that U.S. forces might be able to start leaving Iraq before the end of the year - if daunting conditions including subdued violence and political reconciliation are met.
He also said that the buildup in troops is "not the last chance" to succeed in Iraq and added, "I would be irresponsible if I weren't thinking about what the alternatives might be."
The Pentagon is in the midst of implementing Bush's order to raise troop levels by 21,500, part of a plan to help quell sectarian violence in Baghdad.
New checkpoints were in evidence yesterday in Iraq's capital city, and there were reports of inspections of increased numbers of vehicles. At the same time, more than 50 people were killed or found dead during the day, and Prime Minister Nouri al-Maliki said insurgents were responding to the new security measures by killing as many people as possible.
The war has claimed the lives of more than 3,000 U.S. troops so far, and officials announced two more deaths. The casualties included a soldier killed Tuesday at a security post southwest of Baghdad and a Marine who died Monday in Anbar province.
Bush's decision to dispatch additional troops has become a flash point for critics of his Iraq policy in the new, Democratic-controlled Congress, whose lawmakers were elected last fall by a war-weary electorate.
When congressional Democrats began their campaign to challenge Bush over the unpopular war last month, House leaders decided to defer to the Senate to pass a resolution first.
But on Monday, Republican senators derailed consideration of a nonbinding, bipartisan resolution that criticizes the Bush plan by preventing Democrats from getting the 60 votes needed to bring up the measure.
Yesterday, with few signs that the impasse would end soon in the Senate, House leaders said they might move first on an issue that Americans say is the most pressing one facing the nation.
"We said for a long period of time we would follow the Senate, but we believe it is important for us to make ... our views known," House Majority Leader Steny Hoyer of Maryland said at his weekly briefing with reporters.
House Speaker Nancy Pelosi has told her colleagues that a resolution against the president's call for 21,500 additional troops would be just the first of several legislative actions intended to pressure Bush into starting to withdraw U.S. combat forces from Iraq.
Despite the mounting pressure, Senate Republicans continued to insist yesterday that they simply want a fair debate on the floor of the Senate.
As they did Monday, they complained that they were not being allowed to bring up two alternatives to the resolution crafted by Republican Sen. John W. Warner of Virginia that "disagrees" with the president's plan to send more troops into Baghdad to control the sharply escalating sectarian violence.
One of the other resolutions - sponsored by Sen. John McCain, an Arizona Republican who backs the troop buildup - supports the new strategy but also expresses the need for the Iraqi government to meet certain benchmarks to prove its commitment to help the American effort.
The third resolution was offered by Republican Sen. Judd Gregg of New Hampshire and is a short resolution that opposes any limit on funds for U.S. troops in the field.
But Senate Democrats hammered Republicans on Monday for ducking a formal debate on the war. And by yesterday morning, some Republicans worried that the public would misunderstand their stance.
"It's very unfortunate that we appear to be blocking," McCain complained. "I hope we can make the American people aware that we're just asking for votes on our amendment, which is the way the Senate works."
Noam N. Levey and Janet Hook write for the Los Angeles Times. The Associated Press contributed to this article.