LAST WEDNESDAY, the Supreme Court heard arguments in two of the biggest cases this term. First, the court considered the constitutionality of an Ohio program providing vouchers to low-income parents who enroll their children in church-related schools. Then, the court reviewed the constitutionality of a Virginia law under which a retarded man, convicted of a capital crime, received a death sentence. A common theme in accounts reporting the two arguments concerned one justice in particular–Sandra Day O’Connor. The focus on her was justified. Both cases may well turn on her vote, a point not lost on either the opposing counsel or the justice’s colleagues. The lawyers made arguments designed to appeal to her even as her colleagues none too subtly asked questions of the lawyers–or simply made statements–intended to incline her their way. In the vouchers case, for example, Justice David Souter, an all-but-certain vote against the Ohio program, said that “what bothers me and Justice O’Connor” is that “a massive amount of money goes to the religious schools,” notwithstanding that it is the parents who decide where to enroll their children, and that they may opt for nonreligious schools. Justices rarely are so ungrammatical–“me” should come second in that conjunctive phrase–but it is explainable: Souter probably had uttered “me” before suddenly realizing the need to work in O’Connor. Characteristically, O’Connor said nothing about whether Souter’s concern was hers, too. Last June, Jeffrey Rosen of the George Washington University Law School wrote a profile of O’Connor titled, “A Majority of One.” She is a majority of one because it is her vote on a narrowly divided court that has decided so many of the most divisive legal issues in American life–those involving race, religion and abortion. As Rosen makes clear, however, her influence lies not merely in the fact that she casts so many swing votes but also in how she goes about making her decisions. And how is that? Like the Arizona legislator she once was, she is interested first and foremost in taking in all of the facts. Having sifted them all, she exercises judgment–but only very narrowly. The promulgation of legal doctrine–of “bright-line” rules–isn’t her interest. As she said in a speech last fall, “The rule of law must . . . be flexible enough to adapt to different circumstances.” To some, O’Connor’s approach to judging may seem exactly right. Why not take in all of the facts and rule narrowly? But there is more to consider–another fact, if you will–in assessing her approach. It is that narrow judgments create legal instability that leads to further litigation, which, rising to the Supreme Court, keeps the court–and “the majority of one”–in business. O’Connor’s approach inevitably leads to judicial supremacy. That point is worth noting in the context of Supreme Court nominations. O’Connor was Ronald Reagan’s first appointee. Reagan came to office vowing to appoint justices committed to judicial restraint. It is possible to point to O’Connor opinions that fit that description. But taken as a whole, her career on the court has been less in service of restraint than supremacy. It is striking that from the same hand–Reagan’s–has come two such different justices– O’Connor and Antonin Scalia, a 1986 appointee. While it is true that in many cases the two have been on the same side, indeed a “conservative side,” politically speaking, the two have come to their conclusions via much different routes, ones with major implications for the role of the court. For Scalia, as he famously titled a law review article, “The rule of law is a law of rules.” A rule of law constrains not only lower courts but also the judge who writes it. For Scalia, that includes himself. “If the next case should have such different facts that my political or policy preferences regarding the outcome are quite the opposite,” he says, “I will be unable to indulge those preferences. I have committed myself to the governing principle.” Today, those who advised Reagan on judges will say–privately, of course–that Scalia is more what Reagan had hoped for in a justice. Nonetheless, it is O’Connor, not Scalia or someone who shares his approach to judging, whom court watchers tend to see as the odds-on favorite to replace Chief Justice William Rehnquist, should he step down. Thus, the Rehnquist Court would become the O’Connor Court. Which, of course, it already is. Terry Eastland is publisher of The Weekly Standard