"When she's on the bench people will see a fantastic woman who is honest, open, humble and capable of being a great Supreme Court judge," Mr. Bush told reporters at the White House.
Asked he if would rule out ever seeing Miers' name withdrawn, Mr. Bush did not answer directly substituting instead words of confidence about her confirmation process. "She is going to be on the bench," he said. "She'll be confirmed."
Mr. Bush spoke after William Kristol, editor of the conservative Weekly Standard, called for Miers to consider withdrawing from the nomination.
Meanwhile, Miers and her supporters worked the phones and knocked on doors to rally conservatives who argue that Mr. Bush has reneged on his promise to name justices with proven records as strong conservative.
"It's the Souter factor," said Sen. Jeff Sessions, R-Ala., referring to Supreme Court Justice David Souter, a little-known judge nominated for the court by the first President Bush who later turned out to be a liberal justice.
"I think conservatives do not have confidence she has a well-formed judicial philosophy, and they are afraid she might drift and be a part of the activist group like Justice Souter has," Sessions said Friday. "She will need to articulate a vision of the Constitution and the role of a judge that is sound or she could be in trouble with the Republican senators."
Miers met Friday with Sen. Conrad Burns, who called her an "outstanding woman" when Mr. Bush first revealed her as his pick. "Ms. Miers has a great sense of humor and a great understanding of the importance of the legal arena in our nation," the Montana Republican said after meeting her.
Because the 60-year-old Miers spent her career in private practice and as a member of Mr. Bush's White House staff, conservatives outside the nation's capital have little to hang their hopes on except the president's word that she would be a justice in the mold of Antonin Scalia or Clarence Thomas.
"She's got to convince the conservative world that she understands the word 'strict constructionist,'" said Sen. Lindsey Graham, R-S.C., one of three Judiciary Committee conservatives who met Thursday with Miers. "She's going to have to fill in those blanks and create a comfort level."
Mr. Bush defended his White House counsel as "an extraordinary nominee" and a "very bright woman."
"I'm confident she's going to be a Supreme Court judge who will not legislate from the bench and will strictly interpret the Constitution," the president said after a meeting in the Oval Office with the prime minister of Hungary.
Among those calling on Mr. Bush to nominate someone other than Miers to replace retiring Justice Sandra Day O'Connor is the anti-abortion group Operation Rescue, which has promised an active campaign to persuade the president.