WASHINGTON – A bipartisan group of 14 senators on Monday averted a historic and potentially debilitating Senate showdown over judicial nominations by agreeing to retain Senate rules that give extra power to political minorities.

The deal, struck in the offices of Sen. John McCain, R-Ariz., permits votes on three of five of President Bush’s nominees to federal circuit courts of appeal that Democrats have blocked, including Priscilla Owen of Texas. Democrats already had agreed to grant votes on two other blocked judges. The deal also would retain the use of extended debate against judicial nominees – a tactic that requires 60 out of 100 votes in the Senate to overcome and which Democrats have used to prevent votes on 10 of Bush’s nominees for appellate courts.

The seven Democratic negotiators agreed that they would use the maneuver, called a filibuster, only in “extraordinary circumstances.” In exchange, the seven Republicans, including Maine Sens. Susan Collins and Olympia Snowe, said they would vote against efforts this year or next to do away with the filibuster altogether on judicial nominations.

The extraordinary bargain thwarted a partisan confrontation that could have altered significantly how the Senate governs itself, strengthened Bush’s ability to put a conservative stamp on the federal judiciary and shifted the government’s balance of power more in favor of the White House.

“We have reached an agreement to try and avert a crisis in the United States Senate and pull the institution back from a precipice that would have had, in the view of all 14 of us, lasting impact, damaging impact on our institution,” McCain said.

Collins described the negotiations leading to the compromise as “long and difficult.” She said the centrist senators took the unusual step of negotiating one on one with no staff involvement.

“We sat down day after day working on the language. We developed trust and bonds that helped us forge the agreement,” she said.

“What mattered most to me was that we preserve the traditions of the Senate, and that we avoid a bitter partisan debate, so that now we can get on with the people’s business,” Collins said. “I come home to Maine every weekend and hear people concerned about base closures and other important issues. That’s why we needed to avoid a crisis for the Senate, so we can address those issues.”

Snowe, in a prepared statement, said the agreement serves as an example of how government should operate.

“Today, we have reaffirmed that, while our constitutional democracy is premised on majority rule, it is also grounded in a commitment to minority rights,” Snowe said. “With this agreement, we preserve long-standing senatorial rights while eliminating the obstruction that has held up nominations to our federal courts. This compromise ensures that the very rules of the Senate that encourage the type of consensus building embodied by this agreement remain intact.”

The deal was a defeat for Bush, who on Monday again had demanded straight up-or-down votes on all of his nominees. It also was a blow to religious conservatives, who have advocated for more socially conservative judges and who put considerable pressure on Senate Majority Leader Bill Frist, R-Tenn., and Senate Republicans to change the filibuster rule. The Christian conservative Family Research Council had e-mailed supporters asking them to “pray that no compromise will be allowed which will let this unprecedented use of the filibuster remain.”

In addition to Owen, the seven Democrats said they would vote to end debate on Janice Rogers Brown, who has been nominated to the District of Columbia Circuit Court of Appeals, and William Pryor to the 11th Circuit Court of Appeals. Two other nominees, however, William Myers and Henry Saad, would continue to be blocked.

Tony Perkins, the Family Research Council’s president, said he was disappointed by the deal but argued that in permitting votes on Owen and Brown, the Democrats had suggested that both were not the type of “extraordinary circumstance” that would deserve a filibuster.

“I don’t think it’s over,” he said. “They kicked the can down the road a little bit.”

Frist, who initiated the move to alter the Senate rules, said he was pleased that some judges would get up-or-down votes, but said he was disappointed that the question of judicial filibuster hadn’t been settled once and for all.

Senate Democratic leader Harry Reid of Nevada praised the agreement as a “victory for democracy.” Earlier in the day he said he had all but given up hope that the negotiations would yield an agreement.

“There is nothing more exhilarating than being shot at and missed,” said assistant Democratic leader Richard Durbin of Illinois.

The agreement was forged by an unusual coalition of centrists, iconoclasts and Senate institutions. The negotiations were led by McCain, a Republican maverick known for bucking Bush and his GOP leaders, and Sen. Ben Nelson of Nebraska, who over the past four years has been the Democrat most likely to vote with Republicans. The group also included two of the most venerable voices of the Senate: Sen. Robert C. Byrd, D-W.Va., and Sen. John Warner, R-Va.

Two of the Republican participants, Sens. Mike DeWine of Ohio and Lindsey Graham of South Carolina, said they’d been prepared to vote to change the filibuster on Tuesday had a deal failed.

“Here’s what I know is going to happen next: People at home are going to be very upset at me for a while,” said Graham, a McCain ally who occasionally parts ways with other Republicans.

By having seven Republicans and seven Democrats, the deal assured that Frist wouldn’t have enough votes to change the filibuster rule and that Democrats wouldn’t have enough votes on their side to continue to block most of the judges. There are 55 Republicans, 44 Democrats and one independent in the Senate.

Earlier on Monday, the Senate debated all day and into the night over Bush’s judicial nominations in anticipation of the looming vote. Custodians rolled cots into the Capitol in preparation of an all-night session that would lead to the showdown.

That vote now will not occur. Instead, the Senate is expected to vote to end debate on Owen, a Texas Supreme Court justice whose nomination to the 5th Circuit Court of Appeals had been blocked by Democrats for four years. That will defuse Frist’s threat to alter the rules, a gambit that senators called a “nuclear option” because of its potential for legislative devastation.

Also signing the agreement were Republican Lincoln Chafee of Rhode Island and Democrats Mark Pryor of Arkansas, Joseph Lieberman of Connecticut, Mary Landrieu of Louisiana, Daniel Inouye of Hawaii and Ken Salazar of Colorado.