WASHINGTON (AP) – Senate Republicans set the stage for a showdown Tuesday on the filibusters blocking several of President Bush’s judicial nominees, a historic vote that could determine whether an out-of-power party can stop a president from placing like-minded jurists on the nation’s highest courts.

Unless compromise-minded centrists can strike a deal before then, Senate Majority Leader Bill Frist will force a test vote Tuesday on Texas judge Priscilla Owen’s nomination to the 5th U.S. Circuit Court of Appeals.

Under the expected chain of events set in motion Friday: If the nomination doesn’t garner 60 votes – the threshold for overcoming a filibuster – Frist then will have the presiding officer, expected to be Vice President Dick Cheney in his role as Senate president, declare that filibusters are illegal for Supreme Court and federal appellate court nominees.

The Republican majority presumably then would uphold that ruling, a procedure that has become known as the “nuclear option” because senators say it would blow up relations between the two parties.

“The Senate clock centered above the vice president’s chair is in a countdown, second by second, to the appointed hour and minute when a nuclear explosion may render the Senate inoperative, or at least do substantial damage to this institution,” said Judiciary Chairman Arlen Specter, R-Pa.

In Maine, Republican senators Olympia Snowe and Susan Collins were hoping dramatic measures would not be necessary.

Sen. Collins said Friday she would like to see a compromise between the parties instead of an outright ban. Specifically, Collins said she will push for reforms that would limit filibusters to only extreme circumstances.

“I have concerns about changing rules. I also have concerns about some of the democrats overusing the filibuster,” Collins said. “I’m really eager to achieve an agreement that will allow the senate to back off this kind of confrontation.”

Collins said she is working with 11 colleagues – six Democrats and five Republican – in crafting such a compromise. The senator believes such an agreement would be a better resolution for the current filibuster issue than continued bickering.

“To put everybody through this, it’s just not helpful,” she said. “It doesn’t serve the American people at all.”

Sen. Olympia Snowe was back in Maine on Friday for the weekend. Press secretary Antonia Ferrier said before heading back to Washington next week, Snowe intended to stay in touch by phone with other centrists concerned about the possibility of a “nuclear option” by phone. Several other senators were leaving town for the weekend.

Snowe attended a half-dozen meetings last week with the “group of 12” in an effort to reach a compromise that would keep the filibuster rule change from going to a vote Tuesday,, Ferrier said.

After the last meeting of the group Thursday, Snowe sounded “pretty positive,” Ferrier said.

No staffers, only senators, were allowed in the meetings, Ferrier said.

Staff writers Christopher Williams and Mark LaFlamme contributed to this report.