Once upon a time, a Republican president distrustful of big government and enthralled with markets nominated a seemingly conservative man named Roberts to the Supreme Court. The president hoped and expected that long after he left the Oval Office, Justice Roberts would continue to do the work of his conservative movement. But Justice Roberts bitterly disappointed his erstwhile supporters, rejecting claims of states' rights against the national government and defending the rights of minorities against the assertions of the national security state.

A liberal fantasy? Hardly. The president was Herbert Hoover and the justice was Owen Roberts, who, in the famous “switch in time that saved nine,” sided with the majority in two critical 1937 cases that reversed the Court's long-standing hostility to progressive legislation. In 1944, Roberts dissented from the Court's infamous decision in Korematsu v. United States, which upheld the forced removal of persons of Japanese ancestry from their homes on the West Coast to “relocation centers” in the nation's interior.

Might John Roberts follow in the footsteps of Owen Roberts? By now Republicans no doubt fret that this is a well-beaten path. In addition to Roberts, Earl Warren, William Brennan, Harry Blackmun, and, to a lesser extent, Sandra Day O'Connor, Anthony Kennedy, and David Souter, have all disappointed Republican presidents by turning liberal -- at least on particular issues -- once safely ensconced in their respective Supreme Court seats.

There is some reason for liberals to be hopeful (and thus for conservatives to worry) about Roberts. Having observed several of his oral arguments in the Supreme Court, I agree with the nearly universal consensus that he is a brilliant lawyer. Gifted lawyers are sometimes ideologues, but overwhelming ideological commitments typically interfere with good lawyering. To make arguments effectively requires an ability to respond to the arguments of one's adversary, which in turn requires an ability to see -- and thus see what is wrong with -- the adversary's point of view. In his 1993 book, The Lost Lawyer, former Yale Law School Dean Anthony Kronman associated this consummate lawyer's ability to simultaneously hold conflicting views in one's mind with a spirit of moderation and toleration. If Kronman is right, then -- as someone with the capacity to understand and articulate a range of views on nearly every issue -- as a justice, Roberts might be expected to rule differently on different issues, perhaps following in O'Connor's pragmatic, nonideological pattern.

That is a possibility, but a faint one. In anticipation of a Supreme Court vacancy, conservative groups have for years been rallying to the cry of “no more Souters.” David Souter was, of course, a “stealth candidate” in the sense that he lacked an extensive paper trail that purported to express his own personal views. Yet he proved too stealthy even for his supporters, for it turned out that Souter was and is a New England moderate.

Some on the far right drew the lesson that stealth candidates should be avoided at all costs, demanding a reliable movement conservative on record as calling for the reversal of Roe v. Wade, the invalidation of affirmative action, and the curtailment of gay rights. But this was never going to be a viable political strategy for a GOP that needs to curry favor with its religious conservative base without alienating the moderate center of American public opinion. What George W. Bush and the Republicans needed was a one-way stealth candidate, someone whose personal views on key constitutional issues were known by the administration to be reliably conservative but who appeared to outsiders as a cipher.

Has Bush found his one-way cipher in Roberts? Judging by the chatter on the news networks and the blogosphere, the answer appears to be yes. Democrats and liberal interest groups are calling for a full airing of the Roberts judicial philosophy, while Republicans and conservative groups are rallying to his defense under the banner of a “dignified” confirmation process (as though it is somehow undignified to ask a person nominated to a lifetime seat on the Supreme Court to explain what role he believes precedent ought to play in constitutional interpretation).

I doubt that President Bush directly sought from Roberts a commitment on particular issues, and as I share the general view of Roberts as a man of integrity, I am certain that if he were asked, he wouldn't have provided such assurances. So how can movement conservatives be confident that Roberts will vote as one of them?

The short answer is that they cannot be wholly confident, but the longer answer is that they can take considerable comfort from the company Roberts keeps. He clerked for then-Associate Justice William Rehnquist when Rehnquist was clearly the Court's most conservative member. He spent most of his career in the federal government, but only during Republican administrations. Thus, while Roberts is entitled to say that briefs he wrote, including those calling for the overruling of Roe, were in the service of a policy set by his political bosses, skeptics are equally entitled to ask why Roberts chose to work for these and not for other bosses.

Michael C. Dorf is the Michael I. Sovern Professor of Law at Columbia University. His 2004 book, Constitutional Law Stories tells the stories behind 15 leading constitutional cases. His next book, No Litmus Test: Law and Politics in the Twenty-First Century, will be published in early 2006.