WASHINGTON – A group of moderate Republicans – and some old GOP bulls who’ve labored under Democratic as well as Republican control – hold the fate of President Bush’s judicial nominees in their hands.

Majority Leader Bill Frist, R-Tenn., is irked that Democrats have used filibusters to block 10 of Bush’s choices for federal appeals courts.

He’s vowed not to let it happen this year, particularly with the possibility that there could soon be a Supreme Court nominee to consider. But to carry out that promise might require changing Senate rules that now allow just 41 members to block any judicial nominee.

Frist needs 50 votes in the 100-member Senate to change the rules. Vice President Dick Cheney could then break a tie.

But getting 50 votes from the 55 Republicans is no sure thing. Many are nervous about what has become known as the “nuclear option,” a rules change would set off a political war that might block the remainder of Bush’s domestic agenda.

GOP Sens. Arlen Specter of Pennsylvania, John McCain of Arizona, Olympia Snowe and Susan Collins of Maine, John Warner of Virginia and Lincoln Chafee of Rhode Island have either said they oppose changing the rules or have declined to promise to support the change.

Veteran Sens. Thad Cochran of Mississippi and Richard Lugar of Indiana won’t say either.

“I’ll cross that bridge when I come to it,” says Alaska’s Ted Stevens, elected to the Senate in 1970 and now its longest-serving Republican.

Even some GOP senators who say they would support a change appear hesitant about it, knowing it would be used against them in the future.

“We know someday we’ll be in the minority,” said Energy Committee Chairman Pete Domenici. “But some of us are willing to say let it be the case for both and let us rule by majority vote with reference to judicial appointees.”

Republican Sen. Mitch McConnell of Kentucky and former Majority Leader Trent Lott of Mississippi support the rules change and think they can help Frist get the 50 votes he needs.

“If the leader decides we have no other option, I believe we’ll have the votes,” said Lott, the Rules Committee chairman.

Democrats, however, would still hold enough power to retaliate. Democratic leader Harry Reid of Nevada said Frist wouldn’t be able to get Bush’s legislative proposals through the Senate if the GOP had its way on all judges.

Reid said of the possible rules change, “It would mean that one man, sitting in the White House, has the practical ability to personally hand out lifetime jobs to judges whose rulings can last forever.”

“That’s not how America works.”

One of the most contentious nominees – Texas Judge Priscilla Owen – praised as an ideal candidate by conservatives but called pro-business and anti-abortion by liberals, is up for committee approval April 7. William Myers of Idaho, whom Democrats call one of the most anti-environment judicial nominees they’ve seen, has already been approved by the Judiciary Committee.

In the nuclear option – some supporters call it the “constitutional” option – Frist would push through a rules change that would eliminate Senate filibusters for judicial nominees.

Democrats have been using filibuster threats, a promise to stall a nomination through extended debate, on 10 Bush judicial nominees. Such a threat requires 60 votes to overcome. The Senate did confirm 204 of the president’s 214 trial and appellate judicial nominees.

Taking away the filibuster would mean Republicans would need 50 votes to confirm judges, well within the number of their 55-member caucus.

Many conservatives want Frist to make the change quickly, in case of a Supreme Court nomination. Chief Justice William Rehnquist, 80, is fighting thyroid cancer.

Lack of certainty in the confirmation process could make Bush choose someone who is less conservative, said Sean Rushton, executive director of the conservative Committee for Justice.

“If the president is pressured by a 60-vote hurdle, he may choose an Anthony Kennedy versus an Antonin Scalia,” he said.

Frist and other GOP senators let the first months of the year go by talking more about negotiating with Democrats than about ramming their solution through. And Frist suggested last month that he might offer a compromise that would limit debate time on nominees, followed by a final confirmation vote.

Democrats are unlikely to agree.

If Frist succeeds, Democrats have made clear they will retaliate, all but shutting down the legislative process and stifling Bush’s second-term goals.