WILLIAM H. REHNQUIST arrived at the Supreme Court in 1972 at the height of an era of aggressive judicial liberalism. By the time of his death Saturday, the court had become controversial as much for its conservative instincts as for its remaining liberal ones. President Richard M. Nixon chose Mr. Rehnquist because of his reputation, as Mr. Nixon less than gracefully put it, as a "mean and rough" right-winger. True to form, Justice Rehnquist, who as a Supreme Court clerk had written memos to Justice Robert H. Jackson arguing against school desegregation, began his judicial career in often lonely dissents famous for their hard edge. But as chief justice, a position he assumed in 1986, he ably managed a philosophically divided but increasingly conservative court and oversaw an era of profound change in the nation's jurisprudence. We disagree with many of his opinions and votes, and some of the tendencies of the Rehnquist Court have wrought real damage. But in important respects, the broad change he ushered in was necessary.

The chief justice's death comes at an awkward moment, with the confirmation hearings for his former law clerk, Judge John G. Roberts Jr., about to commence. The unfortunate fact of two vacancies makes it important that the Senate proceed with the Roberts hearings and that President Bush move quickly to name a new chief justice.

Under Chief Justice Rehnquist's leadership, the court restrained itself in areas of earlier excess: It became far less free-wheeling in its embrace of novel claims of new rights. But critically, the Rehnquist Court did not by and large reverse the controversial precedents it inherited. Rather, it generally reinforced them. The overall message was that even as the court repudiated the methodology of its earlier era, the historic opinions of that era stood.

This attitude separated the chief from Justices Antonin Scalia and, particularly, Clarence Thomas -- the other members of the court's right flank. The chief was more pragmatic and politically savvy than the other two, and some conservatives came to resent what they considered his failures of principle and his tendency to write around inconvenient doctrine. But this very flexibility, combined with his undoubted administrative skills in running the federal judiciary, was a big part of his effectiveness as chief. The chief justice's pragmatism should not be overstated; the fact that the Rehnquist Court was not more radical was as much a reflection of the power of the court's centrist justices, Anthony M. Kennedy and the retiring Sandra Day O'Connor, as it was of the chief's own attitudes. In other words, he often didn't have the votes. Still Chief Justice Rehnquist often chose statesmanship over ideology, and despite the shrill fears of his detractors, there was no radical transformation of the law.

The Rehnquist Court, to be sure, developed its own areas of excess, and, like its virtues, these to a great extent reflected the chief justice's instincts. The court's consistent blind eye to the rights of accused criminals, for example, reflected both his constrained vision of federal protections and his breezy deference to state courts even when they produced manifestly unjust results. His solicitude for states' rights and curtailing federal power portends great problems if taken too far. Ironically, the high court these days -- though professedly more restrained than in prior eras -- actually strikes down more acts of Congress than it did in its liberal activist days. This reflects both the fact that the court in the past was more concerned with unconstitutional behavior by the states, rather than the federal government, and the fact that the Rehnquist Court was not always as restrained as its rhetoric. And while the court's intervention in the 2000 election was a complicated affair, many liberals regard it as a searing moment of judicial politicking winning out over the conservative majority's stated judicial approach.

Still, it is wrong to dismiss the changes the Rehnquist Court brought about as simply reflecting conservative politics. They go far deeper than that and reflect, however imperfectly and inconstantly, a legitimate concern with having the court -- which is, after all, composed of unelected and unaccountable judges -- not exceed its place in a democratic society. Chief Justice Rehnquist was not a philosophically pure or altogether consistent champion of this reorientation, but it is the legacy of the court that bears his name. Warts and all, it is a considerable achievement.