WASHINGTON – President Bush went to bat yesterday for his second nominee to the Supreme Court, Harriet Miers, assuring Republicans who have questioned the pick that the 60-year-old White House counsel is eminently qualified and reliably conservative.

Mr. Bush spoke about his nominee to replace Justice O’Connor at a rare, 55-minute press conference at the White House yesterday morning. He brushed aside the suggestion that Ms. Miers, a prominent Dallas attorney who was the commissioner of the Texas Lottery Commission before following Mr. Bush to the White House five years ago, is unqualified for the court. He denied that cronyism played a role in his selection.

“I picked the best person I could find,” Mr. Bush said.

“When it’s all said and done,” he said, “the American people are going to know what I know: This woman deserves to be on the bench, and she’ll bring credit to the bench and to the law.”

Mr. Bush’s meeting with reporters, his first since May, came as a number of prominent conservatives have hammered his nominee for what they describe as her lack of judicial experience and for her apparent reluctance over a three-decade legal career to stake out overtly conservative views on a number of hot-button social issues that have come before the court.

A conservative icon, Rush Limbaugh, suggested on Monday that Mr. Bush chose Ms. Miers from a position of weakness and complained in an on-air interview with Vice President Cheney that a more conservative nominee would have exposed weaknesses in the Democratic Party and its views on the court. Mr. Cheney hinted that the president would save a more strident pick for another, later appointment.

“We looked at a very broad range of candidates,” Mr. Cheney said, “and, frankly, I hope we have additional vacancies down the road that the president will be able to fill, and some of those people you mention will be, I expect, on everybody’s short list.”

Contributors and editors at a number of conservative magazines shared Mr. Limbaugh’s view. Speaking on CNN, a senior editor at National Review, Ramesh Ponnuru, said Mr. Bush’s “trust me” message didn’t cut it.

“That might be enough for a monarch,” Mr. Ponnuru said, “but it’s plainly not a persuasive argument in a democratic system.”

Senate Republicans yesterday sought to allay conservative concerns by lining up behind the nominee. A Republican member of the Judiciary Committee, Senator Cornyn of Texas, took to the floor in the morning to defend Ms. Miers’s record. A former chairman of the committee, Senator Hatch of Utah, endorsed her later in the day, as did the majority whip, Senator Mc-Connell of Kentucky.

Senate Democrats were disarmed by the choice of Ms. Miers because their leader in the Senate, Senator Reid of Nevada, recommended her to Mr. Bush as a potential candidate during a breakfast meeting two weeks ago with Senate leaders. Mr. Reid said Monday that the recommendation was not meant to be viewed as an endorsement.

Despite initial signs that Democrats were pleased with Ms. Miers, the party machinery indicated at least one line of attack it will take in coming weeks. The Democratic National Committee issued a press release yesterday afternoon that sought to tar Ms. Miers by her close association with Mr. Bush.

“The question remains whether or not Miers can be independent on the bench, given her close association with the Bush White House,” the communications director for the Democratic National Committee, Karen Finney, wrote.

In fielding questions about Ms. Miers, Mr. Bush focused on her accomplishments as a lawyer, the outside perspective she would bring to a court that is dominated by former judges, and her work in vetting his other nominees. This last point was cited by several conservative supporters of Ms. Miers as reason enough to back her for the job.

Republican support for Ms. Miers has been consistent, but not firm. One of the most conservative members of the Judiciary Committee, Senator Brownback of Kansas, has floated increasingly skeptical statements about Ms. Miers since Monday’s announcement. Mr. Bush reportedly assured Mr. Brownback during a party at the home of Defense Secretary Rumsfeld that he would be happy with his pick.

“There’s precious little to go on and a deep concern that this would be a Souter-like candidate,” Mr. Brownback told the Associated Press yesterday, in a reference to the liberal Supreme Court justice nominated by Mr. Bush’s father. “The circumstances seem to be very similar: not much track record, people vouching for her, yet indications of a different thought pattern earlier in life.”

Soon after Mr. Bush’s announcement, reports began to surface about Ms. Miers’s past contributions to Democratic political candidates and to her support, while running for Dallas City Council in 1989, of full civil rights protections for gays. Republicans sought to counter those reports by pointing out that Ms. Miers had donated money to a pro-life organization the same year. An official with that group said the donation was typical among political candidates at the time.

“This was a banquet with a 1,000 people, and a lot of them voters,” the president of the Texans for Life Coalition, Kyleen Wright, said. “A lot of politicians would have wanted to be there. For me, it’s not a real high comfort level. The jury is still out for us on her.”

In his press conference, Mr. Bush appeared eager to placate the critics of his pick without worrying Democrats who have warmed to her. Mr. Bush sidestepped answering whether he had ever spoken with Ms. Miers about abortion, saying he “has no litmus test.” And he hinted that she would not disappoint the conservatives she has worked with over the past decade by shifting her ideological allegiances if confirmed to the court.

“I know her well enough to be able to say that she’s not going to change, that 20 years from now she’ll be the same person with the same philosophy that she is today,” Mr. Bush said. “She’ll have more experience, she’ll have been a judge, but, nevertheless, her philosophy won’t change. And that’s important to me.”