Republican lawmakers and top Senate aides, speaking privately for the most part, said the uproar from the right was becoming an impediment for Specter, a Pennsylvania lawmaker who has coveted the chairmanship. They said while it was likely he would still get the post, it was no longer a certainty.

"He is not out of the woods," said one Senate aide who is closely monitoring developments on the Judiciary Committee, echoing a sentiment expressed by Republican senators as well as other party officials.

Most of those Republicans said they initially believed that Specter's subsequent clarification - that he did not mean his remarks as a warning to Bush not to nominate to the Supreme Court a judge who would be inclined to overturn the Roe v. Wade decision - would protect him. But they said continuing resistance to his taking the chairmanship of the committee that examines judicial nominees was being fanned by conservative talk-radio hosts and activist groups outraged over his comments in the immediate aftermath of resounding Republican wins on Tuesday night.

Lawmakers and aides said Specter's comments have touched a nerve since Democratic resistance to Bush's judicial nominees was an important element of the Republican campaigns and a factor in the defeat of Sen. Tom Daschle, the Democratic leader, in South Dakota. In addition, the expanded Republican Senate majority is strongly anti-abortion.

The outpouring illustrated how the party's conservative wing has been emboldened by the White House win and the strengthening of Republican majorities in Congress, potentially raising new hazards for moderate Republicans who might want to break from the president or House and Senate leadership on major issues.

Some Republicans on Capitol Hill said the attempt to quickly exert that influence could work in Specter's favor since members of the Senate do not necessarily want their first action after an energizing election to be jettisoning Specter under pressure from outside groups. "We need to show some discipline and not overreact," one said.

The initial comments by Specter on Wednesday, at a news conference, that it would be unlikely that staunch opponents of abortion could be confirmed for the Supreme Court came after Bush campaigned hard for Specter, a backer of abortion rights, to win a primary challenge against a conservative lawmaker and abortion opponent.

But in subsequent interviews, he said that his remark at the news conference merely stated an obvious political fact: that just as Democrats had filibustered judicial nominees before, they could be expected to do the same again, and that Bush was aware of this himself.

"I did not warn the president about anything and was very respectful of his constitutional authority," he said in a written statement on Thursday, adding that he would apply no "litmus test" on abortion.

In interviews this week, Specter said he did not believe his chairmanship was in jeopardy. "I voted for every one of President Bush's nominees in the committee and on the floor, every last one of them," said Specter. He has been contacting his colleagues in an effort to calm the situation.

Specter's status as potential chairman was the subject of discussion on Thursday during a telephone conference call between Senate Republican leaders, who expressed concern about his remarks. Republicans will return to the Capitol the week after next to begin reorganizing for the upcoming session and could address the matter then.

The chairmanship is subject to a vote by the members of the committee and then ratified by all Senate Republicans, who almost always follow seniority in deciding committee leadership. The current chairman, Sen. Orrin Hatch of Utah, is reaching his six-year term limit, and Specter is next in line, with Sen. Jon Kyl of Arizona waiting in the wings.

Given their new 55-45 majority, Republicans also want to increase their numerical advantage on the Judiciary Committee, giving them more leverage to move judicial nominees. With that power, some Republicans said it would be counterproductive to have a chairman who might balk at some of the president's choices.

Sen. Lindsey Graham, R-S.C., and a member of the panel, said he anticipated "healthy discussion" about Specter's comments.

"The original comments attributed to Sen. Specter were very unnerving," said Graham, who said Republicans should not endorse a "litmus test" that they would not accept from Democrats. "His statement clarifying his position is reassuring and I hope we will work our way through this."

But the conservative groups were not mollified. The Concerned Women of America planned a news conference critical of Specter today in Pennsylvania and Michael Schwartz, vice president of government relations, said his organization would continue to press the case against the lawmaker.

"It is clear to me that with this statement and his past record of performance, Sen. Specter has disqualified himself from any right to be considered as chairman of the Judiciary Committee," said Schwartz.

An alert distributed electronically by the Family Research Council urged its supporters to call Senate leaders and committee members to lobby against Specter. "He has a history of pandering to the aggressive abortion lobby, and a Specter chairmanship would be disastrous," said the group.

Senate offices said the response was intense. "We are getting slammed," said Mike Brumas, a spokesman for Sen. Jeff Sessions, R-Ala. and a panel member. "Some of them are saying things like, they voted for values on Tuesday and this is a slap in the face."

An aide to Sen. John Cornyn of Texas, another Republican who sits on the Judiciary Committee, said the office was getting several calls a minute, a volume equal to the calls during consideration of the proposed constitutional amendment to ban same-sex marriage.

Democrats say they fear that the Bush administration intends to use its second term to nominate judges interested in striking down abortion laws. They view the fight surrounding Specter as a strong indication their concerns are warranted.

"I think Sen. Specter is right, and the fact that there was a negative reaction to his remarks is not a good omen," said Sen. Richard Durbin, D-Ill.