"Judicial activism" ought to have a straightforward meaning. But when foes of Democratic appointees to the U.S. Supreme Court and other seats on the federal bench deploy what has become a catch-phrase, there is an invisible adjective attached - liberal. In other words, their supposedly principled complaint is a dog-whistle.

Whether judicial activism is efficacious or pernicious requires a rather more deeply nuanced discussion than the dog-whistlers want to indulge in. They don't really want to put "judicial activism" up against "judicial restraint" because that would mean assessing, for instance, Roe v. Wade alongside Bush v. Gore. Instead, they've got one thing in mind: propagandizing their audience into viewing the target of their criticism as someone who "makes law from the bench" - another phrase with that same invisible adjective attached.

Two surveys of the Court's decisions put the lie to the idea that "judicial activism" is the bailiwick of liberals. One of them, conducted by Yale Law Professor Paul Gewirtz and Yale grad Chad Golder, reviewed Supreme Court rulings from 1994-2005. In this period, the Court either struck down or upheld Congressional statutes (or provisions of those statutes) in 64 cases:

We found that justices vary widely in their inclination to strike down Congressional laws. Justice Clarence Thomas, appointed by President George H. W. Bush, was the most inclined, voting to invalidate 65.63 percent of those laws; Justice Stephen Breyer, appointed by President Bill Clinton, was the least, voting to invalidate 28.13 percent. The tally for all the justices appears below.

Thomas 65.63%
Kennedy 64.06%
Scalia 56.25%
Rehnquist 46.88%
O’Connor 46.77%
Souter 42.19%
Stevens 39.34%
Ginsburg 39.06%
Breyer 28.13%

One conclusion our data suggests is that those justices often considered more "liberal" - Justices Breyer, Ruth Bader Ginsburg, David Souter and John Paul Stevens - vote least frequently to overturn Congressional statutes, while those often labeled "conservative" vote more frequently to do so. At least by this measure (others are possible, of course), the latter group is the most activist.

Legal scholar Cass Sunstein and economist Thomas Miles came up with one of those other measures. As one part of their study of left-right bias in judicial decisions, they looked at each Supreme Court justice's record for upholding or striking down federal regulations. Justice Breyer was the most restrained, that is, he upheld the regulation most often; and Justice Scalia was the most activist, choosing to reject a regulation more often than any other justice. (Neither John Roberts or Samuel Alito were included because they were too new to the Court for there to be enough data.) The results:

Breyer 82%
Souter 77%
Ginsburg 74%
Stevens 71%
O'Connor 68%
Kennedy 67%
Rehnquist 64%
Thomas 54%
Scalia 52%

There is a cute trick behind conservatives' shouting of "judicial activism." Big media's chatterati would do well in the coming weeks to remember what that is. You can be certain most of them won't.