The resignation of Justice Sandra Day O'Connor means more than the loss of the most visible centrist on the Supreme Court. It also means the loss of the only justice who has been an elected politician. Before coming to the court in 1981, O'Connor had served in the Arizona Senate for five years, including time as majority leader.

Is that sort of experience important? Last year, at a remarkable seminar at Yale Law School, a group of former Supreme Court law clerks who served a half-century ago discussed the behind-the-scenes story of the 1954 ruling in Brown v. Board of Education. That decision actually took two years to reach. It was unanimous in the end, spanning the full range of ideology on the court from William O. Douglas on the left to Felix Frankfurter on the right. It could easily have been 5 to 4, given the issues at stake, the intensity of views and the breathtaking change the decision represented.

Frankly, if the current court had been serving back then, the decision probably would have been 5 to 4, like so many other highly charged and controversial decisions of recent years. What is the difference? The Warren Court in 1954 had five members who had been politicians -- three former U.S. senators (one of whom had also been a mayor of Cleveland), one state legislator and a former governor, Chief Justice Earl Warren.

The former clerks talked about the way in which Warren, Justices Hugo Black, Sherman Minton, Frankfurter and others worked patiently to build consensus, not just a narrow majority. When it wasn't forthcoming the first time the case was up, they put it off to the next year. Liberals and conservatives alike understood how important it was for society, and for the credibility of the court, to find that consensus and put forward a united front. The fact that several of them had been schooled in an environment of coalition-building -- the legislative process -- was a key to that sensitivity and to the final result.

The Warren court of the 1950s was quite typical of American history up to that point, in that justices often came from political backgrounds. Only one of the nine justices in 1954, Minton, had served on a U.S. court of appeals, and he had been a senator before that. Contrast that with the current Supreme Court -- on which seven of the nine justices have served on a federal court of appeals and one other had service on a state court of appeals. The only current member without a background as a judge, interestingly, is Chief Justice William Rehnquist.

Why the change? Over the past 50 years, the federal courts have increasingly made public policy, from settling details on airborne emissions to intervening in disputes between telephone and cable companies to setting guidelines on abortion and sodomy. The increased policy role has come about in part because Congress has passed the buck on controversial decisions to the courts, and in part because judges, left and right, have been willing and eager to step in to fill vacuums. As our politics have become more ideological and more partisan, lifetime court appointments have thus become more important and valuable.

Choosing judges, especially at the Supreme Court level, has taken on a heightened importance -- and presidents and their partisans want to make sure they know what they are getting. A track record at the federal appeals court level is a much safer predictor of behavior at the next level up than service in the U.S. Senate, or as a governor or in other political office.

But having a court that consists largely or only of nonpoliticians has serious costs for the public. Not only are judges less inclined to think broadly of the country and its social and political divide, they are more likely to look at decisions with tunnel vision, not thinking through the problems of maintaining the court's standing with the public and of implementing difficult and divisive decisions.

Moreover, since much of what the court does is to sort out legislative intent, those without political experience have no real sense of how a legislature works and no direct idea of what legislative intent really means in the crucible of the legislative process. Politicians who have run for office and been in campaigns also know how politics works; the ignorance of basic politics shows up in the court's decisions on political issues such as redistricting.

With O'Connor gone, the Supreme Court will have no politicians and only one member, Stephen Breyer, who has worked in a legislature, as a staffer. Most of the names the White House has floated as possible Supreme Court nominees are, predictably, judges on federal appeals courts. It is time to expand the field to seriously consider people with political backgrounds. Former senators John Danforth and Warren Rudman would be superb choices. At least two current senators, John Cornyn of Texas and Jon Kyl of Arizona, fit the ideological criteria of the White House. Harry Reid, the Senate Democratic leader, has mentioned other capable Republican senators, including Mike DeWine of Ohio and Lindsey Graham of South Carolina. There are many others, including present and former governors, senators and House members, who could also fit the bill. The court, and the country, would be well served to have a politician or two on the bench.

The writer is a resident scholar at the American Enterprise Institute.