Senate Democrats plan to delay the Judiciary Committee's vote on Samuel Alito's nomination to the Supreme Court for at least a week, slowing what could have been a quick confirmation process for President Bush's pick to replace retiring Justice Sandra Day O'Connor.

Senate Judiciary Chairman Arlen Specter had hoped to hold a committee vote on Alito's nomination on Jan. 17, a little over a week from the Monday start of the federal appellate judge's confirmation hearings.

But Senate Minority Leader Harry Reid, D-Nev., told Majority Leader Bill Frist, R-Tenn., on Thursday that Democrats will invoke their right to hold the Alito committee vote over for one week, Senate leadership aides told The Associated Press.

The aides spoke on conditions of anonymity because the move had not been announced yet.

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Frist had been pushing for a Jan. 20 confirmation vote for Alito in the full Senate. The date of the Senate's confirmation vote would also have to be delayed if the Democrats follow through on their plan to delay.

The Supreme Court is in recess until Feb. 21.

Reid spokesman Jim Manley, when contacted, refused to comment. Calls to Sen. Patrick Leahy of Vermont, the Judiciary Committee's top Democrat, were not immediately returned.

During the confirmation process for now-Chief Justice John Roberts, Republican and Democratic senators agreed not to delay the committee vote on his nomination by using the customary one-week delay. No such agreement was reached on Alito.

The move is the latest in a tactical battle between Republicans and Democrats over Alito's nomination. The longtime conservative lawyer and judge will face the Judiciary Committee on Monday for his confirmation hearings to become the 110th Supreme Court justice.

Democrats haven't completely given up the notion of blocking Alito's nomination to the Supreme Court, though they're certainly not talking about it before his confirmation hearings.

"I don't think anybody today sees a reason for a filibuster, but they may after the hearing if the answers are troubling to them or they feel they haven't gotten the answers to important questions," said Carl Tobias, a University of Richmond law professor.

Democrats contend Alito is too conservative and could undermine some rights if confirmed. Some of their liberal supporters have urged Democrats to do whatever they can to block the nomination, including a filibuster.

It takes 41 votes to sustain a filibuster. With the Senate split with 55 Republicans, 44 Democrats and one Democratic-voting independent, Democrats could launch an Alito filibuster with no GOP votes.

Democrats have said repeatedly they don't plan to filibuster Alito's nomination, although they also have refused to promise to refrain from the stalling tactic on the federal appeals court judge.

"I don't think it's wise for members to try and outline a strategy other than to make sure these hearings are comprehensive and they're done with dignity and respect for the nominee," said Edward Kennedy, D-Mass. "The future will take care of itself."

The final decision will be made after the hearings, said Charles Schumer, D-N.Y., head of the Democratic Senatorial Campaign Committee.

"If he is out of the mainstream and will use his tremendously powerful position as Supreme Court judge to impose his views on the American people, then there's a potential for a filibuster, and no one really knows that until the hearings," Schumer said.

Republicans say they're ready to fight, including the so-called nuclear option, which would let the GOP ban judicial filibusters. "I will use all the tools I have to simply get an up-or-down vote on the floor of the Senate for the president's judicial nominees," Frist said in January.

To be successful, a filibuster would need almost all of the 44 Democrats behind it and certainly all of the Democratic leaders. But the Senate's senior Democrat, Robert Byrd of West Virginia, has said several times on the Senate floor that he has seen no reason to filibuster Alito's nomination.

Other Democrats have echoed that since Alito's October nomination.

In addition, the "Gang of 14" — centrist senators who brokered a deal last year to keep Frist from banning filibusters — has splintered, with at least two of the Republicans saying they would vote to ban filibusters if Democrats try one on Alito.

Frist needs a majority vote in the Senate for such a ban. If all 100 senators voted, Democrats would need 51 votes to stop Frist. No Republicans have said they would even consider opposing Alito.

To pull off a successful filibuster, Democrats need things to go their way both inside and outside the hearings, said Julian Zelizer, a Supreme Court expert at Boston University.

When it comes to abortion and voting rights, Zelizer said, "If he is too hostile, if he's too confrontational, if he fails to convey the sense that he's evolved on these issues since the 1980s, there is a chance that Democrats will see this as reason to filibuster," he said.

Events outside the hearing also will have an influence, Zelizer said, especially the guilty pleas of Jack Abramoff, the once-powerful lobbyist who has agreed to testify in a political corruption investigation.

It could "increase the willingness of the Democrats to be even tougher in the Alito hearings, sensing that the Republican leadership is in trouble," Zelizer said.

Meanwhile, Democrats announced several witnesses for the Alito hearing, including Beth Nolan, a White House counsel for President Clinton; Harvard Law School professor Laurence Tribe; National Bar Association president Reginald Turner and Kate Michelman, former president of NARAL-Pro Choice America.