President Bush's nomination of Harriet Miers for the Supreme Court splintered the Republican Party's conservative base, with reaction from key senators and groups ranging from hostility to silence to praise.

Several right-leaning lawmakers and activists seemed bewildered by the choice of a relatively little-known White House counsel who has given money to Democratic candidates and who was recommended for the job by Minority Leader Harry M. Reid (D-Nev.). While numerous senators urged colleagues to withhold judgment until more is known, some outsiders vented their dismay that the president had not chosen someone with unmistakably conservative credentials.

"I know of nothing in Harriet Miers's background that would qualify her for an appointment to the Supreme Court," said Roger Pilon, founder of the libertarian Cato Institute's Center for Constitutional Studies. William Kristol, editor of the influential conservative magazine Weekly Standard, summarized his reaction as "disappointed, depressed and demoralized."

In the Senate, which will confirm or reject Miers this fall, the nomination triggered a mixture of praise and reserve that, on balance, seemed to bode well for her confirmation, veteran staffers said. The acclaim she received from GOP leaders was expected, they said. Less predictable were the accolades from Reid, the Democratic leader, and several conservative Republicans on the Judiciary Committee.

"My conversations with Harriet Miers indicate that she is a first-rate lawyer and a fine person," said Sen. Jeff Sessions (R-Ala.), one of the committee's most conservative members. "Her legal skills are proven, and her reputation throughout the legal community is excellent." Sen. Lindsey O. Graham (S.C.), another committee Republican, said Bush "has made a solid pick for the Supreme Court."

But two other committee conservatives withheld judgment. Sen. Tom Coburn (R-Okla.) issued a two-sentence statement saying that Miers "deserves a fair and thorough hearing and confirmation process" and that "I look forward to learning more about her qualifications and judicial philosophy." Sen. Sam Brownback (R-Kan.) made no public comment despite several media requests.

The praise from Reid, who voted against Chief Justice John G. Roberts Jr.'s confirmation last month, turned heads in both parties. "I have to say without any qualification that I'm very happy that we have someone like her," Reid told reporters as he greeted Miers in the Capitol.

Earlier in the day, Judiciary Committee Chairman Arlen Specter (R-Pa.) said Reid had "recommended her nomination to the president" in a White House meeting two weeks ago. Reid spokesman Jim Manley said the Democratic leader had "urged the president to consider" Miers.

Miers's supporters tried to appease conservatives by releasing information suggesting she opposes abortion rights. Publicist Keith Appell issued a statement saying: "According to Kyleen Wright at Texans for Life, Harriet Miers gave $150 to the organization -- then known as Texans United for Life -- in 1989. Miers was a bronze patron for their annual dinner in which Henry Hyde was the keynote speaker." Hyde, a congressman from Illinois, is a leading opponent of legalized abortion.

Wright confirmed the contribution yesterday, but said, "I'm not sure it says anything one way or the other." Wright said most of the roughly two dozen bronze contributors were candidates, and Miers at the time was on the Dallas City Council.

Tony Perkins, president of the Family Research Council, issued a statement expressing the ambivalence of several groups on the right. "President Bush has long made it clear that his choices for the U.S. Supreme Court would be in the mold of current justices Antonin Scalia and Clarence Thomas," Perkins said. "We have no reason to believe he has abandoned that standard. However, our lack of knowledge about Harriet Miers, and the absence of a record on the bench, give us insufficient information from which to assess whether or not she is indeed in that mold."

Gary Bauer, 2000 presidential candidate and president of American Values, said, "The future of the Supreme Court is too important to leave to chance."

In private, some conservative leaders voiced concern that Miers could become "another David Souter," the Supreme Court justice picked by President Bush's father who has turned out to be a reliable member of the court's liberal wing. They pointed to her 1988 contributions to Democrat Al Gore's presidential campaign, the reelection campaign of Sen. Lloyd Bentsen (D-Tex.) and the Democratic National Committee. The 1988 Democratic platform endorsed abortion rights.

Some groups on the right flatly opposed Miers's confirmation yesterday. "We must reject the nomination of Harriet Miers to the Supreme Court," said Troy Newman, president of the antiabortion group Operation Rescue. "Miers is no Thomas or Scalia."

Two prominent conservatives, however, endorsed Miers. James Dobson of Focus on the Family said, "We welcome the president's nomination. . . . [Bush] promised to select competent judges who will 'not use the bench to write social policy.' . . . We believe that she will not prove to be a lone exception."

Almost unanimously, leaders on the left said senators must press Miers to make explicit her judicial philosophy and her stands on the right to privacy and civil rights.

"If she is confirmed, Harriet Miers may cast the deciding vote in cases that will determine whether women and minorities have equal opportunity in education and the workplace, whether we can be free and equal members of society, and whether we can make our personal and private family decisions without government intrusion," said Debra L. Ness, president of the National Partnership for Women & Families. "Senators have a duty to ask probing questions and learn Miers's views before voting on her nomination."

In a statement, the liberal Alliance for Justice said: "Ms. Miers must prove that she can put her years of service to President Bush and powerful corporate interests behind her and be an independent voice on the court. The burden is on Harriet Miers to demonstrate her fitness for a seat on the Supreme Court to the Senate and the American people. There is a tremendous amount at stake. Our rights and liberties hang in the balance."

White House counsel Harriet Miers waits for an elevator in the Capitol with Ed Gillespie, chairman of the Republican National Committee. Miers's past contributions to Democratic campaigns raised concerns among some Republicans.