However grudgingly, President Bush accepted responsibility for the role of federal authorities in bungling the Hurricane Katrina evacuation and relief efforts. One might have thought that such responsibility would include, at a minimum, the recognition that important positions in the government -- that of, say, head of the Federal Emergency Management Agency (FEMA) or, I don't know, Supreme Court justice -- ought to be filled by people whose qualifications include something besides loyal support for the president. If so, one would have thought wrong.

Perhaps that's unfair. Miers is undoubtedly a much more able attorney than FEMA's disgraced Michael Brown was a manager. And if confirmed, Miers would hardly be the first justice to ascend to the high court with no prior judicial experience. Many justices -- including Felix Frankfurter, William O. Douglas, Abe Fortas, Earl Warren, Lewis Powell, and William Rehnquist -- served with distinction after joining the Court as juristic novices.

What distinguishes Miers from many of her predecessors is that she appears to have been chosen because of rather than in spite of her judicial inexperience. Believing he needed a nominee with no paper trail, Bush turned to someone whose views and values he likely knows well from their close professional association over the last decade, even as they remain completely unknown to the public at large.

That asymmetry alone obligates the Senate to question Miers closely. What does she mean when she says that the courts must “strictly” apply the law and the Constitution? Are prior judicial precedents part of the law to be applied strictly? Having vetted John Roberts, no doubt she has recently given some thought as to how best to answer such questions.

Speaking of the new chief justice, senators -- including those who voted for the Roberts confirmation -- should vote “no” on Miers if she is as reticent in her responses as he was in his. No doubt the White House and Miers' supporters will accuse the Senate of sexism in applying a different standard to a man and a woman. But in fact, there are three reasons wholly unrelated to gender to treat the nominees differently.

First, although Roberts may have been intended as a stealth candidate, by the time the National Archives was done releasing material, he had an extensive paper trail. The picture that emerged was of a keenly intelligent, deeply conservative, and intense young man whose style, and possibly his outlook as well, softened somewhat over the course of a distinguished career of advocacy and a brief career of judging.

By contrast, to date we have no statements whatsoever by Miers that would give even a hint about her present disposition on such questions as a constitutional right to privacy, the legality of race-based affirmative action, or the proper division of authority between the state and federal governments. Roberts attributed some of his most controversial prior statements to his role as a lawyer, but at least senators had the statements to evaluate. Miers will come before the Senate as a virtual tabula rasa, and so extensive questioning will be needed even to bring her to the point of Roberts-like opacity.

Second, Roberts was confirmed to fill the seat vacated by the late Chief Justice Rehnquist, a deeply conservative jurist. Even if Roberts turns out to be as conservative as his supporters hope and his critics fear, his appointment will not substantially alter the balance of the Court.

Again by contrast, Miers has been named to replace Justice Sandra Day O'Connor, who is the fulcrum of power on a closely divided Court. A Justice Miers thus has the potential to shift the Court and the country dramatically to the right in a way that Chief Justice Roberts, by himself, could not.

Third, and meaning no personal disrespect to Miers, she lacks the professional experience that so obviously qualified Roberts for the job.

To say this is not to say that women are less qualified than men to be Supreme Court justices. There certainly are women who could hit the ground running there.

For example, Bush could have named Washington lawyer and former Rehnquist clerk Maureen Mahoney, whose record as a Supreme Court advocate rivals that of Roberts. But despite her solidly conservative credentials, picking Mahoney would have angered true believers, because she successfully represented the University of Michigan Law School's affirmative-action program before the Court.

By the same token, in his weakened political position, President Bush could not nominate a clear down-the-line conservative like Judge Edith Jones for fear of provoking a filibuster or worse, a straight-out “no” vote by Democrats and defecting Republicans.

Thus, the president may have felt that he had no other choice but to go with the stealthy Miers. If so, so much the worse for the president. The Senate, however, does have a choice.

Michael C. Dorf is the Michael I. Sovern Professor of Law at Columbia University and the author of Constitutional Law Stories. His next book, No Litmus Test: Law and Politics in the Twenty-First Century, will be published in early 2006.