Lawmakers from both sides of the aisle on Friday conceded that while most Senate Democrats will oppose confirming Samuel Alito to the Supreme Court, there is not enough support within the party to sustain a filibuster that would prevent a vote on his nomination.

That means the 3rd U.S Circuit Court of Appeals judge could be confirmed by the full Senate as early as next Tuesday.

Senate Majority Leader Bill Frist has called for a Monday cloture vote that would end debate on the nomination and set the stage for final vote Tuesday. With 60 or more votes in favor of cloture — which Republicans believe they have — the threat of a filibuster by some Democrats would be quashed. Whereas it takes a simple majority of the Senate to confirm a nominee, it takes 60 votes to end a filibuster mounted to delay a vote.

"Next Tuesday, a bipartisan majority will vote to confirm Judge Alito as Justice Alito," said Frist of Tennessee.

"We're going to have a vote Tuesday morning," Senate Democratic Leader Harry Reid of Nevada said during a U.S. Conference of Mayors event. "Everyone knows there are not enough votes to support a filibuster, but it's an opportunity to people to express their opinion on what a bad choice it was to replace Sandra Day O'Connor."

Alito's confirmation has become a political battle as well as a judicial one, with top Democrats like Massachusetts Sens. Ted Kennedy and John Kerry calling for a filibuster. They continued to try to round up support within their caucus Friday for blocking Alito but that effort wasn't gaining much ground.

"While I personally cannot support Judge Alito's confirmation on the Supreme Court, there is not a smoking gun in his past that would warrant 'extraordinary circumstances' and subsequently a filibuster against his nomination," said Sen. Mark Pryor, D-Ark., a member of the so-called "Gang of 14" centrist senators from both parties who have vowed to prevent filibusters on any nominee unless some "extraordinary circumstance" arises.

"I have faith in the 13 other members who forged the 'Gang of 14,'" Pryor continued. "In exchange for preserving the minority party's right to filibuster a judge, we all agreed a higher threshold must be met before this action is taken."

Democrats have said that by replacing retiring Justice Sandra Day O’Connor, Alito would dangerously shift the ideals of the court too far to the right, away from the 1973 ruling in Roe v. Wade that is the underpinning for legal abortion, and too much in favor of a strong executive branch, among other complaints.

Kerry, in a 27-minute Senate speech after returning from the World Economic Forum conference in Switzerland, urged Democrats to take a stand. "This is a fight worth making, because it is a fight for a lifetime appointment to the Supreme Court," he said.

White House spokesman Scott McClellan on Friday called Kerry's threat "the first-ever call for a filibuster from the slopes of Davos, Switzerland."

Around midday Friday, Senate Democrats said Kerry and Kennedy do not have enough votes to deny an up or down vote. In order to successfully "extend debate," or filibuster the nomination, they must round up at least 41 votes. At least 10 Democrats are opposed to a filibuster.

"I do not think a filibuster will be successful," Democratic Sen. Kent Conrad of North Dakota said after announcing his intention to vote against the filibuster effort. "A filibuster is not going to be sustained."

At least 65 Senators are expected to vote to end debate and move on to Tuesday's confirmation vote; that's five more votes than the minimum needed for cloture.

Republicans have steadily called for an up-or-down vote to send the nomination to the full Senate without a filibuster. The Republicans appear to stand on solid ground, with none of the 55 Republican senators publicly opposing Alito, and at least three Democrats — Robert Byrd of West Virginia, Tim Johnson of South Dakota and Ben Nelson of Nebraska — voicing support. On Friday, Conrad said he was leaning toward voting for Alito.

"It is clear to me that a majority of the American people and the people I represent support his confirmation," Conrad said after meeting with Alito in his office.

Senior Republican Sen. Ted Stevens of Alaska also threw his support to Alito Friday. Stevens said he closely monitored Alito's commitment during his confirmation hearings to "respect" past rulings when it comes to Roe v. Wade.

"As I vote to confirm his nomination, I do so under the assumption that Judge Alito will uphold this commitment," said Stevens, who supports abortion rights.

'There's Some Division in Our Caucus'

If Kennedy and Kerry's efforts to filibuster Alito's nomination succeed, that would essentially kill the nomination.

While possible filibuster leaders were counting Sens. Russ Feingold, D-Wis., Dick Durbin, D-Ill., Dianne Feinstein, D-Calif., and Debbie Stabenow, D-Mich., as supporters of a filibuster, others have stayed quiet, including Judiciary Committee top Democrat Patrick Leahy of Vermont and Charles Schumer of New York.

"I think it’s a matter of being on the record, and I want to be on the record" as using every procedural means to block the nomination, Durbin told FOX News on Friday. "More and more Americans are understanding how critically important this decision is … remember, this is a lifetime appointment."

He added: "Taking an additional hour or an additional day to go through the process is not unreasonable."

Democratic Sens. Mary Landrieu of Louisiana, Daniel Akaka of Hawaii, Joe Biden of Delaware, Ken Salazar of Colorado and Byron Dorgan of North Dakota — as well as GOP Sen. Olympia Snowe of Maine — made it clear they would not support a filibuster, even though Akaka and Salazar oppose Alito and the others are undecided.

"There's some division in our caucus," Kennedy conceded. "It's an uphill climb at the current time, but it's achievable."

Reid has earlier offered little support for a filibuster, saying there had been enough time to debate the nomination and that, "no one can complain on this matter that there hasn't been sufficient time to talk about Judge Alito, pro or con."

But he seemed to change his tune on Friday when he said he would support a filibuster should an opportunity come around.

"Harry Reid's position on Judge Alito's confirmation has more holes than a slice of Swiss cheese," said Republican National Committee spokeswoman Tracey Schmitt. "After stating an unwillingness to support a filibuster, it looks as though the Davos Democrats were able to twist Reid's arm enough to switch him from 'filibuster ... not me,' to 'filibuster ... oui, oui.'"

Reid also said Alito was a "bad choice" and that the president should have taken into more account First Lady Laura Bush's idea to nominate a woman to replace O'Connor.

Republicans immediately began criticizing Democrats for even considering a filibuster.

"The Democrat leadership knows that Senators from both parties will join together to defeat any attempt to filibuster the nomination of Judge Alito. So these continued threats of obstruction are petty and partisan," said Sen. John Cornyn, R-Texas. "Judge Alito deserves better than this stunt; he deserves better than a desperate attempt by a partisan minority to save face with their hard left base."

Nevertheless, the vote for Alito could be tight. Comparatively, in last fall's vote for Chief Justice John Roberts, 22 Democrats voted against Roberts, and in 1991, Justice Clarence Thomas was confirmed in a 52-48 vote.

Alito, 55, has testified for 18 hours and answered more than 700 questions in a weeklong hearing before the Senate Judiciary Committee. The Tuesday-morning final vote would be only hours before President Bush's State of the Union address.

Bush has repeatedly called on the Senate to confirm his nominee.

Alito "understands the role of a judge is not to advance a personal and political agenda," the president said Thursday at the White House. "He is a decent man. He's got a lot of experience and he deserves an up-or-down vote in the Senate."

FOX News' Molly Hooper and Greg Kelly and The Associated Press contributed to this report.