With the fate of judicial filibusters hanging in the balance, just seven Senate Republicans remain publicly undecided on changing the rules to eliminate the parliamentary move.

And with only two Republicans officially on the record as opposing the rule change, Majority Leader Bill Frist (R-Tenn.) appears to need the support of four of the seven remaining undecided Senators in order to pass the change by the slimmest of margins.

Those stark numbers have left Democrats scrambling to create public pressure on the undecided Republicans to oppose Frist’s move, which could come as early as next week, while Republicans continued to remain confident that, if push comes to shove, they will have the votes on the floor to win.

“At this stage, it’s a really close call,” Minority Leader Harry Reid (D-Nev.) conceded Friday.

Interviews with 17 Republican Senators last week — those identified by Democratic aides as potential “no” votes — revealed that a large number of Republicans would rather avoid a politically bloody floor fight over the issue, fearing that the fallout from what opponents call the “nuclear option” would destroy any remaining comity in the chamber. Frist’s biggest obstacle to victory is convincing those wavering Senators that he has done everything he can to reach a compromise and that Reid simply refuses to yield, leaving him no other alternative.

Reid’s biggest problem is that after several weeks of a coordinated campaign involving millions of dollars of advertising by liberal activists and near-daily press conferences attacking the pending rule change, only two Republicans have stated their outright opposition to the rule change.

Sens. John McCain (R-Ariz.) and Lincoln Chafee (R-R.I.) are the lone “no” votes Frist is facing at this point, although both of them left the slightest possibility that the leader could talk them into it. “I will listen to leadership, but I’m opposed,” McCain said last week.

Chafee offered a similar line, saying: “I’m always willing to listen, I guess.”

Because the maneuver to change the rules will probably entail getting a ruling from the chair — likely to be occupied by Vice President Cheney — Democrats will need to garner 51 votes to overturn the ruling and thus retain the right to filibuster judicial nominees. That leaves Reid in search of four more Republicans opposed to Frist.

Of the 17 GOP targets for Democrats, six Senate Republicans stated last week they are behind Frist, albeit with some reservations about the potential fallout. Sen. Gordon Smith (R-Ore.) called his support for Frist a “qualified yes,” noting he has encouraged Frist to seek a compromise.

“We’ve got to find a way so we can both save face and keep our institution from being dysfunctional,” Smith said.

Sen. George Voinovich (R-Ohio) said he also backed Frist but hoped that Democrats would yield to some sort of compromise that would allow the majority to stop short of invoking the option dubbed “nuclear” by opponents and “constitutional” by proponents.

“If push finally comes to shove, many of us will support the constitutional option,” Voinovich said, adding, “By golly, we’ve done everything we can and if we have to, we’ll do it.”

A big setback for Democrats came Thursday when Appropriations Chairman Thad Cochran (R-Miss.) issued a statement endorsing Frist’s effort. Considered an institutionalist who was wary of changing rules on a party-line vote, Cochran told Roll Call on Monday night he was undecided. “It’s something that hasn’t matured,” he said.

Less than 72 hours later, Cochran put out a statement backing Frist.

Three other Republicans representing swing states — Sens. Norm Coleman (Minn.), Chuck Grassley (Iowa) and Judd Gregg (N.H.) — voiced their unequivocal support for Frist. Summing up their views, Coleman said last week that Democrats had started this political war by filibustering 10 of President Bush’s nominees in 2003 and 2004, the largest judicial blockade by filibuster ever.

“That’s the nuclear option. They dropped the nuclear bomb last year,” Coleman said.

Sens. Mike DeWine (R-Ohio) and John Sununu (R-N.H.) have both made their decisions but declined to state them publicly. DeWine said remaining silent might help spur negotiations between Frist and Reid.

“I’ve pretty much made up my mind,” he said. “I’m still hopeful this thing can get negotiated.”

GOP aides privately said they are confident Sununu and DeWine would back Frist, considering Sununu is a solid conservative vote on most issues and DeWine is a member of the Judiciary Committee — home to the heated, extremely partisan fights over Bush’s judicial nominees for the past four years.

If Sununu and DeWine went with Frist, that would leave seven GOP votes up in the air: Sens. Susan Collins (Maine), Chuck Hagel (Neb.), Dick Lugar (Ind.), Lisa Murkowski (Alaska), Olympia Snowe (Maine), Arlen Specter (Pa.) and John Warner (Va.).

Snowe has been the most publicly reluctant to go along with the nuclear option of the seven, leading her to often be counted as a “no” vote by Democrats and many media outlets. A member of the GOP minority in the House for 16 years before winning her Senate seat in 1994, Snowe fears what a rule change on a partisan vote could lead to when Republicans end up back in the Senate minority.

But, when asked to specify her position, Snowe said she just didn’t want to talk about it. An aide confirmed that Snowe has reached no final decision.

Collins is in a similar position, and she pointedly declined to comment on any aspect of the potential rule change last week.

If Democrats picked off Snowe and Collins, in addition to McCain and Chafee, that would leave the fate of judicial filibusters in the hands of just five Republicans, with Democrats needing to sway only two to block the move.

Lugar, Specter and Warner all declared last week they remain undecided on the issue, reiterating their desire for a compromise.

“I’m considering it very carefully. I’ve encouraged our leader to use every diplomatic means possible,” said Lugar, the Foreign Relations chairman.

Warner, the Armed Services chairman, said that he was “still doing my research” and that he had no idea when he’d make up his mind.

Specter — who issued a statement in November saying there was sufficient precedent to change the rules unilaterally — said he wasn’t taking a position because he was, as Judiciary chairman, trying to help broker a compromise. “I haven’t taken a position. To do that would be to undercut my ability to work through this,” he said.

Aides said it would be highly unusual for important committee chairmen to buck leadership on a vote that had become such a priority for them.

Murkowski, whose narrow re-election win came with strong support from Frist and Senate leadership, said she wants Frist to do everything he can to avoid the showdown.

“I want to make sure the leader has the time that he needs to utilize every option,” she said.

Murkowski blamed Democrats for the showdown, saying they need to back off their filibuster threats, but she admitted she has reservations.

“I don’t like the thought that we might have to do it,” she said.

And Hagel, who is widely considered to be eyeing a 2008 presidential bid, declined to say which side he was backing in the judicial fight. “I’m with Chuck Hagel,” Hagel joked, adding that, like so many others, he would rather not have to make the choice.

“I’ll make a decision if and when it comes up,” he said.