Senate Democratic leader Harry Reid (search) has privately told individual Republicans he doesn't intend to block votes on any Supreme Court nominees except in extreme cases, according to officials familiar with the conversations.

At the same time, Reid has declined in private — as well as in public — to offer the type of firm no-filibuster assurance that might help him prevail over Majority Leader Bill Frist (search), R-Tenn. in a struggle over President Bush's conservative court appointments and rules covering future confirmations.

The disclosures illustrate the challenge facing the Nevada Democrat, who is struggling against a GOP attempt to change Senate procedures so court candidates can no longer be subjected to the 60-vote requirement of a filibuster (search).

As leader of a minority, Reid needs the support of wavering GOP senators if he is to force a compromise or win a showdown on the Senate floor. Yet he also must take into account members of his own rank and file as well as activist groups that are adamant about preserving their right to block votes on Bush's current and future nominees.

"I can never say there will never be a filibuster because I cannot say that," he said recently on the Senate floor. "But I don't think this Senate is in the mood for a number of filibusters."

While no vacancy currently exists on the Supreme Court, two justices are in their 80s, and one of them, Chief Justice William Rehnquist (search), has thyroid cancer.

As a result, the maneuvering over seven appeals court nominees is widely viewed as prelude to a struggle over the future of the high court.

Democrats successfully filibustered 10 of Bush's first-term appeals court candidates, and seven of them have been renominated. Democrats are threatening to filibuster again, and Republicans may seek a vote to prevent it, a sequence of events that could set up a clash with far-reaching consequences.

Reid upset some of the Democrats' customary allies recently when he offered to allow confirmation of three of the seven stalled nominees in exchange for concessions from Republicans. Chief among the concessions would be a guarantee to leave the filibuster rules unchanged.

Frist found the offer unacceptable.

"We do not want a deal cut. We have worked too hard, because we see these nominees as really extreme," said Nancy Zirkin of the Leadership Conference on Civil Rights. "We have worked too hard to not only defeat them but to keep them off the bench."

Yet Republicans hold 55 seats in the Senate, and Reid will need the votes of at least six of them to prevail. So far, two Republicans, John McCain of Arizona and Lincoln Chafee of Rhode Island, have broken ranks, expressing concern about a change that could permanently reduce minority rights in the Senate. Vote counters in each party say Olympia Snowe of Maine also is likely to side with Democrats.

One Republican, describing a private conversation with Reid, said the Nevada Democrat left the clear impression that, barring an extreme case, he wouldn't sanction a filibuster against a future Supreme Court nominee. But he also refused to make a no-filibuster pledge when asked, according to the senator, who spoke only on condition of anonymity and remains publicly uncommitted on the vote.

Senate aides said they knew of similar conversations with other senators.

Like Reid, Frist also confronts conflicting pressures.

A potential presidential contender in 2008, he courts conservative groups that will wield influence then and want to quickly confirm Bush's nominees now.

Two weeks ago, he appeared by videotape before an event organized by the Family Research Council, "Justice Sunday — Stopping The Filibuster Against People of Faith." Reid accused him in advance of playing "radical Republican politics," but in his speech, Frist retorted, "I don't think it's radical to ask senators to vote. "

As Senate majority leader, Frist has responsibility for carrying out the agenda of an administration that seems ill-disposed to any deal. "We believe that every judicial nominee deserves an up-or-down vote," Karl Rove, Bush's closest political adviser, told USA Today recently after Reid had offered his compromise.

At the same time, Frist must make sure he has the votes to win a showdown, if it comes to one, by holding enough support from wavering Republicans such as John Warner of Virginia, Arlen Specter of Pennsylvania, Susan Collins of Maine, Chuck Hagel of Nebraska and Lisa Murkowski of Alaska.

"We need to act together as senators to define what is best for the institution," Murkowski wrote recently in the Anchorage Daily News.

In part to show flexibility to fellow Republicans, Frist, too, offered a compromise. He proposed retaining existing filibuster rules for district court nominees while guaranteeing a yes-or-no vote for appointees to the appeals court and Supreme Court.

Reid swiftly denounced it as "a big fat wet kiss to the far right."

Asked afterward whether there were additional compromises he could offer, Reid seemed less that definitive.

"The answer is, not at this point," he said.