This information does not tell us everything we need to know. Thomas shows the strongest partisan bias, but is he also an activist? Does he vote to strike down agency decisions at a high rate? To test for judicial activism and judicial restraint, we examined all the data to find which justices are most likely to strike down agency decisions.

It turns out that Breyer wins the award for Judicial Restraint. Surprisingly, the award for Judicial Activism goes to . . . Justice Scalia.

Not all that much depth, but you get a very strong sense of how things are operating in the judicial system, and it's not good.

This evidence offers three important lessons.

First, widespread conservative complaints about “liberal judicial activism” should be taken with many grains of salt. If we ask how often the justices vote to strike down agency decisions, Scalia and Thomas, the most conservative members of the Supreme Court, show the most activist voting patterns. By contrast, the justices commonly described as “liberal” are the least activist.

Of course, there are other measures of what makes a judge “activist,” and I do not claim that our method cannot be challenged, but it is useful to offer some statistical tests, which can ensure that critics are not building their conclusions into their definitions.

Second, partisan voting is a serious problem in the federal judiciary. If the EPA issues a regulation that is aggressive in cleaning the air, or if the National Labor Relations Board resolves a dispute in favor of a union, a panel that consists solely of Republican appointees is unusually inclined to strike it down. That’s indefensible. No one should approve of a situation in which the fate of an environmental regulation depends on whether a lower court panel consists of one, two or three Republican appointees.

Third and perhaps most important, federal agencies in an Obama or McCain administration are likely to make a number of decisions that are more liberal than those of the Bush administration. Many decisions will ultimately be challenged in federal court -- and the Republican-appointed judges who dominate the federal bench could well prove to be a big obstacle. On the Supreme Court, for example, Scalia and Thomas might be joined, much of the time, by Roberts and Alito. On key occasions, Kennedy might probably join them as well.

The lower federal courts could prove an even more serious barrier. Those courts have been stocked with appointees of Presidents Ronald Reagan, George H.W. Bush and George W. Bush. The voting behavior of appointees has been clear: They show a distinctive tendency to strike down agency decisions that do not follow a conservative line.

Here, then, is a major warning for the next administration – and a potential problem for democracy itself.null