Senate Democratic leaders on Thursday committed to stay in session through Saturday and perhaps into next week to debate President Bush’s proposed troop surge in Iraq, saying they were calling the bluff of GOP moderates who were demanding the Senate sidestep the upcoming recess to consider the issue.

Majority Leader Harry Reid (D-Nev.) announced he would file a procedural motion Thursday afternoon to allow for a vote on Saturday on whether to move forward on debating the Iraq surge policy, which has been stalled in the Senate for nearly two weeks. Reid said the vote will put all Senators on record over whether they support or oppose Bush’s proposal to increase the troop presence in the region by 21,500.

“We demand an up-or-down vote on the resolution the House is debating as we speak,” Reid said. Reid has notified Senate offices to expect a 2 p.m. vote saturday.

By Thursday afternoon, Democrats and Republicans remained at an impasse over whether they could avoid the Saturday showdown and come up with a bipartisan agreement to debate the troop increase in Iraq. GOP Senate leaders pushed back against Reid’s threat, saying they are unwilling to move forward on his terms.

Rather, the Republican leadership continued to dig in with their demand that Democrats allow them to offer a vote on a competing GOP proposal. They called Reid’s move wrong on timing, substance and process.

“I’ve repeatedly said since we’ve been involved in the skirmish on this issue that we would insist on having a vote on funding the troops,” insisted Minority Leader Mitch McConnell (R-Ky.).

Senate Minority Whip Trent Lott (R-Miss.) called Reid’s latest maneuver “totally unnecessary” and predicted the Saturday vote to press ahead with the House version of the Iraq legislation would fail.

“We could have worked this out in a fair way,” Lott said.

The House is on the cusp of approving a narrowly worded resolution Friday opposing the president’s plan while supporting the U.S. forces fighting in the conflict. The nonbinding legislation is expected to capture the support of the majority Democrats and a share of Republicans.

Reid said the Democrats are pressing ahead for a cloture vote on Saturday, a move that requires the support of 60 Senators, to allow Senators to debate the House version. The Majority Leader said he was moving ahead after several moderate Republicans said they wanted to postpone the first Congressional recess of the 110th Congress to debate the issue.

“This will be there chance — those that are bugging us for a vote — will have their chance on Saturday,” said Senate Majority Whip Dick Durbin (D-Ill.).

“We are calling their bluff — we are staying here,” added Sen. Charles Schumer (N.Y.), the chairman of the Democratic Senatorial Campaign Committee.

If cloture is invoked Saturday, Reid said the Senate will move ahead with the bill either on Sunday or Monday. Reid said Republicans will be forced to consider the House language, but can offer their own versions as amendments to other upcoming bills slated for Senate consideration.

The move could be problematic for Reid on a weekend where several of his own Caucus members are set to hit the 2008 presidential campaign trail. Reid, however, said he wasn’t deterred by prospective absences.

“We’ve noticed everyone,” Reid said. “We hope everyone will be here.”