Sen. John McCain (R-Ariz.) has taken a central role as Senate centrists head into the final days of negotiations to avert the showdown next week on the “nuclear” option for ending judicial filibusters.

With Sen. Trent Lott (R-Miss.) saying he’s pulling back from working on a compromise, McCain has become the GOP point person working with Sen. Ben Nelson (D-Neb.) to find an alternative to the parliamentary fight to end filibusters on judicial nominations, according to Lott and several other Senators.

McCain, who has for four years been an independent broker on Senate matters, separate from GOP leadership and the White House, downplayed his role Wednesday and said Lott was still the “main player” on the talks, along with several other Senators.

“A lot of us are discussing, trying to find some common ground,” McCain said.

At the same time, the Democratic Senatorial Campaign Committee struck back at the GOP with an ad it is e-mailing out to its supporters, called “Out of Control.” The e-mail links the effort to end filibusters to a series of steps by Republicans that Democrats consider extreme, including the ethics charges surrounding Majority Leader Tom DeLay (R-Texas) and the legislative effort to save Terri Schiavo.

The ad closes with the tagline: “Frist and DeLay: gutting ethics rules, threatening judges, changing the rules as they go along. Abusing their power.”

That ad is a rebuttal to a National Republican Senatorial Committee ad that went out this week via e-mail to its supporters that made fun of Minority Leader Harry Reid (D-Nev.), ending with Reid’s head super-imposed on the body of a ballerina as the ad accused the Democratic leader of doing a “political two-step.”

But Lott said he has all but completely pulled out of the compromise effort, saying it was up to Senate Majority Leader Bill Frist (R-Tenn.) to decide to make a deal or call a vote.

“I’ve done all I can and now it’s up to the leader,” he said. “I’m not the one who has to do the deal. It’s above my paygrade now.”

But, Lott added, “McCain’s still churning.”

Frist met with Reid late Wednesday as part of what he said were now daily meeting with his counterpart on the issue. Beyond the two public compromise offers by the leaders, Frist said he and Reid have exchanged “multiple offers and variations back and forth.”

McCain and Nelson met Wednesday and continued to try to round up as many supporters for a potential compromise as possible. But time is running short.

Frist has set next week as the beginning of the battle, when he’ll call up the first contentious circuit court nominee of the year. To avert the showdown, Nelson had been working with Lott to craft a memo that at least six Senators on each side would sign, with Republicans disavowing the nuclear option and Democrats pledging to invoke cloture on almost all of President Bush’s judicial nominees.

But the main stumbling block has been the seven already filibustered nominees who were re-nominated by Bush, and Lott said that no deal on those seven — Nelson had been pushing to get four confirmed — would work because Frist needed to be a party to that deal.

Frist has not publicly moved from his ironclad stance that all nominees must receive an up-or-down vote, and Lott said that any deal with Nelson required Frist’s tacit support because the Majority Leader would be in charge of calling up the nominees.

“You can’t cut him out,” Lott said. “He’s the one who calls them up or doesn’t call them up.”

McCain said that his talks with Nelson and other Republicans were still centered on the same premise, including some number of the filibustered nominees getting confirmed and others not getting confirmed. He suggested that it would be possible to structure a deal without Frist’s involvement.

“It depends on what the agreement is,” he said, declining to elaborate.

For Lott and many Republicans, the two most critical nominees — Owen and California Supreme Court Justice Janice Rogers Brown — are also the most controversial to Democrats.

Lott hinted that there was some chance he would support a deal that allowed Brown and Owen to be confirmed, but jettisoned other nominees.

“Maybe one of those Michigan guys. I don’t know any of them,” he said of the nominees from Michigan who have been filibustered.

But Minority Whip Dick Durbin (D-Ill.) told reporters Wednesday that the biggest concern for Democrats was maintaining the ability to filibuster, calling Nelson’s plan overly vague in its promise to not filibuster except in “extraordinary circumstances.”