Despite nine months of assaults on Democratic filibusters, Senate Republicans are admitting they still don’t have the support within their own Conference to pass a leadership-backed proposal to change the chamber’s rule on nominations.

Even more troubling for those behind the effort to bring an end to filibusters, Republicans are far from securing the 50 votes they would eventually need to execute what has become know as the “nuclear” option, the controversial parliamentary route that would require only a simple majority to end filibusters on nominations.

Senate Majority Whip Mitch McConnell (R-Ky.) and several other leading Republicans conceded Friday, after a nearly 40-hour marathon of debate on the nomination process, that Republican resistance to rules changes is the main obstacle to preventing any attempt to move to either of the options on the floor.

“I think that’s not likely to happen,” McConnell said of either of the proposed changes prevailing. “There is reluctance within our Conference to change the rules.”

Two of the freshmen Senators who took lead roles in the marathon debate, Norm Coleman (Minn.) and Lindsey Graham (S.C.), said Republicans couldn’t produce enough votes on their own to win a majority on either issue. “There’s still a lot of discussion and concern,” Coleman said of the GOP Conference.

“This is a tradition-laden body,” Graham said of both Republican and Democratic Senators.

Frustrated at having no real means of altering the rules within the chamber, Graham said that he and a group of Republicans would file a lawsuit early next year asking the Supreme Court to rule on the constitutionality of filibustering judicial nominations.

That effort, if taken up by the courts, would not produce a result for months, if not longer, leaving Republicans no relief in their short-term effort to break the six filibusters Democrats have launched so far this Congress. Majority Leader Bill Frist (R-Tenn.) said Friday he was still thinking about bringing up his proposal, co-authored by Sen. Zell Miller (D-Ga.), to change Senate rules on filibusters, turning it into a four-step cloture process that would ultimately require just a simple majority for confirmation.

“Yes, we have begun to think about that,” Frist said Friday. “That will, at some point, be taken to the floor.”

Republicans, however, had already backed away from such a vote last week, saying at the start of the debate that the Frist-Miller proposal would come up for a vote, but later abandoning the idea. With Miller the only Democrat supporting the proposal, Republicans knew they had no chance of securing the two-thirds majority required to make a rules change and pass Frist-Miller. But had they gone ahead with the vote for symbolic purposes, they risked the embarrassment of seeing the proposal not even get a bare majority.

Sen. Olympia Snowe (R-Maine) said she doesn’t support the proposed rules change. “I would have serious concerns about that, and I indicated that,” Snowe said, adding that she is also more leery of the parliamentary nuclear route.

Sen. Lincoln Chafee (R-R.I.) agreed. “Our rules are here and it would take extraordinary circumstances to change them,” Chafee said, adding that the parliamentary route is fraught with even greater constitutional peril.

“I am sure that would go to court and there would probably be an injunction,” said Chafee, adding such a scenario “would be an unfortunate circumstance.”

It’s unclear how many of the Republican “Old Bulls” would support either approach, even those who were outspoken in last week’s nonstop debate in an effort to break the filibuster.

Sen. John Warner (R-Va.), who spoke at length on numerous occasions attacking the constitutionality of the filibusters, said he was undecided on Frist-Miller. The idea of using a bare majority parliamentary tactic didn’t sit well with Warner, either.

“You’d better ask someone else,” he said of the nuclear option. “I’m kind of an old traditionalist. I want to think long and hard before I depart from tradition that’s served this institution for 200 years.”

Sen. John McCain (R-Ariz.) also indicated he was undecided on the issue and said he would only focus on it only if it actually came up for a vote, even though the debate has been raging since Democrats launched their first filibuster in February. “I don’t know. I’d have to think about it,” he said.

McConnell said there is strong resistance to the nuclear route, so named because Democrats have warned the fall-out would include a virtual shutdown of the floor and committees if Republicans seek to unilaterally change the rules of the chamber. “There is pretty widespread reluctance among our conference members to go down that path,” he said.

Regardless of the two new filibusters that were officially launched by Democrats on Friday and the lack of GOP support for rules changes, Republicans insisted the debate on nominations was successful.

“Our goal here was to raise the profile of this issue,” said Sen. Saxby Chambliss (R-Ga.), a new member of the Judiciary Committee.

Republicans mustered 53 votes, seven short of the 60 needed, to end filibusters on two circuit court nominees: California judges Carolyn Kuhl and Janice Rogers Brown.

The issue has received more media attention than ever before. ABC News’ “World News Tonight” used the debate as one of its two top stories of the day Wednesday evening. The next morning, ABC’s “Good Morning America” also aired a segment on the issue, including a bit on a camera crew that followed GOP Conference Chairman Rick Santorum (Pa.) around for several hours Wednesday night and Thursday morning.

And Democrats have entered into uncharted waters with at least the quantity of judicial filibusters they have undertaken. In arguing that their efforts to force cloture votes on nominees is nothing new, Senate Democrats issued releases last week showing that since 1968 Republicans have forced a half-dozen nominees to face cloture votes to shut off debate.

In less than nine months this year the Democrats have matched that 35-year total, launching six filibusters of President Bush’s circuit court nominees.

Graham said his long-shot effort at securing a court ruling outlawing the filibuster practice is the only way to take the question out of the political arena, even though that will likely be the reason why the courts won’t take up the issue.

“I understand the court will be very reluctant to get into the affairs of the Senate,” he said.

Graham said he and a group of Republicans will instead try to fashion their suit on the successful one drafted by Sen. Robert Byrd (D-W.Va.) and other lawmakers in the mid-1990s that overturned the line-item veto.

The Republican lawsuit group expects to hire an attorney next month, and McConnell said he would try to push through a provision that would allow Graham and the other plaintiffs — as well as any Democrats that wanted to work against the suit — to accept pro bono legal work.

“I don’t think anybody would object to that,” he said. A similar provision was given to Byrd to fight the line-item veto, as well as to McConnell and McCain in their legal fight over the new campaign finance law.