Senate Republicans moved yesterday to force a showdown they were likely to lose on ending the month-long Democratic filibuster against the judicial nomination of Miguel Estrada -- a step enabling them to start scheduling other business.

While Republicans vowed to continue pressing for a vote to approve the highly contested nomination, their decision to combine the debate with action on other matters appeared likely to take some of the spotlight off the struggle over Estrada's nomination to the U.S. Court of Appeals for the District of Columbia Circuit.

GOP leaders said the Senate will take up a U.S.-Russia treaty on arms reduction today and may schedule debate and votes next week on a bill that would ban a late-term procedure opponents call "partial birth" abortion. Action would be scheduled for the following week on the budget for fiscal 2004. They said the Senate may also soon take up legislation to help faith-based charities, one of President Bush's priorities.

Republicans said they will return repeatedly to the Estrada nomination and predicted they would eventually prevail. But Democrats showed no signs of relenting and predicted the Republicans would ultimately fail.

Democrats said they will have more than enough votes to prevail in Thursday's "cloture" vote to end the filibuster. Republicans need 60 votes to shut off debate and force a vote on Estrada. They have picked up the votes of four Democrats -- Sens. John Breaux (La.), Zell Miller (Ga.), Ben Nelson (Neb.) and Bill Nelson (Fla.) -- but remain at least three or four votes short of 60, according to Democratic nose-counters.

While conceding they are likely to lose Thursday, Republicans contended the vote will be useful in targeting persuadable senators and building pressure for action by making the case that Democrats are obstructing action.

Republicans said they will keep holding cloture votes "for as long as it takes," said Majority Leader Bill Frist (R-Tenn.). "This is not going to go away until we get an up-or-down vote," he added.

But Democrats, who had been pushing unsuccessfully to get the Republicans to end the Estrada debate and move to other business, claimed that their votes to continue the filibuster are solid.

"I am confident that, regardless of how many votes are taken, our caucus is going to hold its position," said Minority Leader Thomas A. Daschle (D-S.D.).

Democrats say they will allow a simple-majority vote -- which presumably would confirm Estrada's nomination -- only if he would answer questions more fully about his legal views before the Judiciary Committee, and if the administration would release copies of memos he wrote while working for the solicitor general's office in the Justice Department during the 1990s. Without this information, Democrats say, the Senate cannot adequately carry out its advise-and-consent duties under the Constitution.

Republicans defend the 41-year-old Honduran-born, Harvard-educated lawyer as highly qualified. They say he has answered questions as fully as many other nominees who have moved easily through the Senate. They accuse the Democrats of trying to scuttle the nomination because Estrada is a conservative.