The Supreme Court has returned to work, and court watchers are again asking the perennial questions: Which justices are most partisan? Who are the real activists?

We have tried to make progress on these questions by examining how the justices vote and letting their records speak for themselves. We explored the justices' voting patterns from 1989 through 2005, an unusually long period of continuity within the court. (No reliable conclusions can be drawn about Chief Justice John G. Roberts Jr. and Justice Samuel A. Alito because they have so few votes.)

Everyone looks at the high-profile constitutional cases, but to get a real sense of how justices approach their jobs, it's best to analyze the more routine, less-visible cases that are often more important to people's daily lives.

For this reason, we examined all cases in which members of the court, using settled principles, evaluated the legality of important decisions by federal agencies, such as the Environmental Protection Agency, the National Labor Relations Board, the Occupational Safety and Health Administration and the Food and Drug Administration.

We used clear and simple tests to code the decisions of these agencies as either "liberal" or "conservative." For example, we counted an environmental regulation as "liberal" if it was challenged by industry as too aggressive, or as "conservative" if it was challenged by an environmental group as too lax.

We used equally simple tests to code the decisions of the justices. If a member of the court voted to uphold conservative and liberal agency decisions at the same rate, we deemed him "neutral," in the sense that his voting patterns showed no political tilt. If a justice showed such a tilt, we deemed him "partisan." If a justice regularly voted in favor of agencies, we deemed him "restrained," because he proved willing to accept the decisions of another branch of government. If a justice was unusually willing to vote against agencies, we deemed him "activist," in the literal sense that he frequently used judicial power to strike down decisions of another branch.

Note that the terms "restrained" and "activist" are purely descriptive, and so permit an objective test of judicial behavior. It is possible that a justice who is restrained, in our sense, is wrong, and that an activist justice is right.

On the basis of the evidence, we are now prepared to award the Supremes. (Drum roll please.)

The Judicial Neutrality Award, for blind justice, goes to Justice Anthony Kennedy. From Kennedy's voting patterns, we are unable to detect even the slightest political tilt. He upholds liberal and conservative decisions at an identical rate -- slightly more than two-thirds of the time. Justice David H. Souter, a fellow GOP appointee, is the runner-up.

Justice Clarence Thomas is the winner of the Partisan Voting Award for the most politically skewed voting pattern. When the agency decision is conservative, Thomas votes in its favor 84% of the time. But when the agency decision is liberal, Thomas votes in its favor merely 38% of the time -- a remarkable 46% swing.

Partisan voting can be found among some of the court's more liberal members as well. Justice John Paul Stevens is the runner-up -- with a 40% swing. When the agency decision is conservative, he votes in its favor 46% of the time; when it's liberal, his validation rate soars to 86%. Stevens' partisan voting rate is nearly the mirror image of Thomas'.

The Judicial Restraint Award, for the most humble exercise of judicial power, goes to Justice Stephen G. Breyer. Overall, he votes to uphold agency decisions more than four-fifths of the time. Notably, Breyer votes to uphold conservative decisions 64% of the time.

The Judicial Activism Award, for aggressive use of judicial power, goes to a most surprising winner: Justice Antonin Scalia. He upholds agency decisions only about half the time. This is an impressively low number. Under established principles, to which all members of the court subscribe, agencies are supposed to get the benefit of the doubt.

According to our tallies, the remaining justices were neither distinctively neutral nor distinctively partisan. Former Justice Sandra Day O'Connor was almost as neutral as Kennedy and Souter. Justice Ruth Bader Ginsburg's votes had a liberal tilt, but not as much as Stevens', and the late Chief Justice William H. Rehnquist's votes had a conservative tilt, but not as much as Thomas' or Scalia's.

Of course, our numbers have limitations, and we can easily imagine reasonable objections. But hard numbers are often better than anecdotes, biography or abstract speculation.

At the very least, it is impressive to see that the votes of Kennedy, nominated by President Reagan, show no political bias at all -- and that Breyer, nominated by President Clinton, has been the champion of modesty and restraint.

Copyright 2007 Los Angeles Times