What is "Judicial Activism"?
Sunday's Boston Globe contained a story--Judging the Judges--in which I and other scholars were quoted on the meaning of "judicial activism":

[T]he charge of judicial activism has become a "ubiquitous epithet" and unhelpful "scare phrase," Georgetown law professor Peter Edelman recently noted in The Washington Post. Constitutional law scholars across the political spectrum tend to cringe at the way the phrase is used in public debate. "It's almost embarrassing for anyone who is a serious thinker about the Constitution to bandy it about," says Harvard University constitutional scholar Laurence Tribe, who has spoken out in defense of the SJC ruling.

"Most people who use the term don't provide a coherent definition of it. It typically means judicial opinions with which they disagree," says Randy E. Barnett, a law professor at Boston University who considers himself a libertarian and a defender of "original intent" in Constitutional matters. [He should have written "original meaning" not "original intent" --RB.]

Still, the charge isn't going away. Though it is misused by partisans, scholars have for generations held serious debates about judicial activism--and have sometimes even found ways to embrace it. In the political fray, the charge of judicial activism is usually made when court decisions are seen to be interfering with the will of the majority as expressed through their elected representatives--when they are seen to be "making law" rather than interpreting it. But judicial activism, says Barnett, "can't just mean striking down decisions of the legislative branch." (The doctrine of "judicial review," enshrined in American jurisprudence by Justice John Marshall in the famous 1803 case of Marbury v. Madison, gives the judiciary the power to override actions of the other branches of government.) "What it ought to mean," says Barnett, "is judicial decisions that conflict with the Constitution, either because they're putting into the Constitution something that's not there, or because they're refusing to enforce what is there." . . .

. . . But some have suggested ways of changing "judicial activism" from a term of partisan abuse to a helpful analytic tool. In an article last spring in the magazine Legal Affairs, University of Chicago law professor Cass R. Sunstein offered a neutral definition of judicial activism. "A decision that is activist is not necessarily wrong," he wrote. "No one thinks that a court should uphold all actions of the other branches and so a court that is activist, in this sense, might be something to celebrate." By extension, a court that is "restrained" -- one that seldom strikes down laws or reverses bad precedents--may be falling down on the job.

For terms like "judicial activism" and "judicial restraint" to have useful meaning, Sunstein argued, they must be modified. "A court that wrongly invalidates statutes might be said to show unjustified activism," he wrote, while one that frequently makes political decisions not remotely tethered to the Constitution might be held guilty of illegitimate activism. Furthermore, a court that wrongly upholds statutes might be said to show unjustified restraint, while a court that frequently fails to uphold clear Constitutional principles is guilty of illegitimate restraint. (The thrust of Sunstein's article was that the Rehnquist Court is acting with "illegitimate activism" -- as did the Warren Court on some occasions.) Of course, Sunstein concedes, such terms do not eliminate the hard work of evaluating the merits of court decisions.
For a recent and excellent exchange between Larry Solum, Jack Balkin and Jonah Goldberg, see Larry Solum's Jargon: Or Why Neither "Judicial Activism" Nor "Liberal" versus "Conservative" Provide Meaningful Focus for Constitutional Debate on the Legal Theory Blog (and the links therein). Here is how he concludes:

The point is that both Jonah Goldberg and Jack Balkin are engaged in a pseudo-debate. The proposition that liberals are more guilty of the sin of judicial activism than conservatives or vice versa is so vague as to be virtually meaningless. This is the kind of debate that invites simplification and rhetorical flourish but resists resolution through reasoned argument.

Nonetheless, I think that Balkin is on to something important. I believe that Balkin's first instinct was right. We can distinguish between judges that read their own values into the constitution and those who follow the rules laid down. We can distinguish between decisions that depart from precedent, text, and original meaning--and those that do not. Our ability to make these judgments is critically important, because it opens the door to constitutional formalism--the depoliticization of the process of constitutional adjudication.
Check it out.