On the eve of a historic hearing on eliminating judicial filibusters, key Senate Republicans said they lacked the votes to change internal rules and remained very reluctant to go the so-called “nuclear” route any time soon.

Their apparent inability to rewrite the rules for handling judicial nominations leaves in doubt the short-term prospects for a pair of circuit court nominees currently facing Democratic filibusters. And, perhaps far more importantly, it makes it increasingly possible that the current rules will be in play if one or more Supreme Court justices retires later this month at the end of the court’s current term, setting up a major showdown over President Bush’s proposed nominees.

While still expressing frustration with the current system, the top Republican vote-counters said it was going to be very difficult to get anywhere near the two-thirds majority required to pass a rules change ending filibusters.

“It’s not likely to happen because it’s going to take 67 votes,” said Majority Whip Mitch McConnell (R-Ky.).

“It’s probably not going to happen,” agreed Sen. Bob Bennett (R-Utah), Chief Deputy Whip.

The Senate Rules and Administration Committee, chaired by Sen. Trent Lott (R-Miss.), will take up the issue of filibusters on judicial nominations today, with its centerpiece being a proposal by Majority Leader Bill Frist (R-Tenn.) that would require just three cloture votes with decreasing margins to require confirmation of judicial nominees. On the fourth vote, a simple majority would be needed.

Up to a handful of Democrats have voted to end the filibuster of either circuit court nominees Miguel Estrada and Priscilla Owen, but Republicans and Democrats said they would expect only one certain Democratic vote to actually change the chamber’s rules: Sen. Zell Miller (D-Ga.), who drafted the resolution that Frist modified into his own proposal.

Sen. John Breaux (D-La.), for example, has been a vocal opponent of the Estrada filibuster, but said Tuesday there is no logical reason to alter the rules solely for judicial nominations and not other legislative matters, saying there is no reason to allow 60-vote minimums on defense appropriations but not on judges.

“You can’t say you’re going to have one set of rules on one issue and another set of rules for another issue. You can’t pick and choose what rules you’re going to apply depending on what the issue is,” said Breaux, a key moderate whose support would be necessary for any alteration of the rules.

Without substantial Democratic support for altering the rules, Republicans would be left with only the “nuclear” option of changing the rules on filibusters. That’s the idea floated by some Senators to bring up a contested nomination such as Estrada’s, let the Democrats object, then ask the chairman — likely occupied at the time by Vice President Cheney — to rule that filibusters of judicial nominations are unconstitutional.

Democrats would object to the ruling, but it would take just 50 votes to win the ruling, if Cheney was there to break a tie.

The problem with this scenario is it’s doubtful, at least as of now, that Republicans could muster the 50 votes for such a maneuver.

Several Republicans have expressed serious reservations about any rules changes, let alone a unilateral partisan maneuver to rewrite the chamber’s precedents.

“I think it’s a very dangerous course to embark on,” Sen. John McCain (R-Ariz.) said of altering filibuster rules, echoing Breaux’s logic that the rational is lacking. “Then logically you could change the rule on the legislative agenda and we would be the same as the House of Representatives.”

Sen. Olympia Snowe (R-Maine) said she would keep an open mind to the different proposals, which she has yet to clearly study, but noted that a strictly partisan move would come back to haunt Republicans.

“Whatever is done has to be done with the long term in mind,” she said. “Majorities are here today, gone tomorrow. Whatever is done has to be done with caution.”

Without pre-judging any of the proposals, Sen. Mike DeWine (R-Ohio), a member of Judiciary, said the ultimate solution had to come through a bipartisan agreement. “This is going to have to get resolved by an understanding between the parties,” he said.

Sen. Lincoln Chafee (R-R.I.) flat out rejected any attempt at rewriting the rules on judicial nominations, saying the culture of the institution needs to changed before the rules are rewritten.

“We have our sacred institutions here. I think the fight over nominees can be resolved in other ways,” he said, laying part of the blame at Democrats over the treatment of former Sen. John Tower’s (R-Texas) bid to be Defense secretary in 1989. But he said Senate Republicans in the 1990s treated Democratic nominees shoddily and Bush so far had done little to ease the bitter feelings on all sides.

“If you sow the seeds of divisiveness, these are the ramifications,” Chafee said.

Even McConnell said he’s not sure at this point whether he would support a unilateral move to change rules. “That’s a big question. All of those options are being considered. I’ve reached no firm decision,” he said.

Bennett said that, for now, there would be no quick move to get a ruling from the chair on judicial filibusters, with the GOP instead putting its hopes on increased political pressure on Democrats, particularly on the Estrada nomination. “Let’s let a little more time go by,” Bennett said. “Let’s just see how that develops because of the price you pay.”

The result of the nuclear route would be a dramatic shutdown of Senate business, Democrats have promised, and such a shutdown could have dramatic political impact.

“No one knows who gets blamed for that,” Bennett said, slightly likening such a scenario to the government shutdowns of 1995 and 1996. “Whichever party gets blamed for that pays a huge political price.”