Correction Appended

NEW HAVEN - WHEN Democrats or Republicans seek to criticize judges or judicial nominees, they often resort to the same language. They say that the judge is "activist." But the word "activist" is rarely defined. Often it simply means that the judge makes decisions with which the critic disagrees.

In order to move beyond this labeling game, we've identified one reasonably objective and quantifiable measure of a judge's activism, and we've used it to assess the records of the justices on the current Supreme Court.

Here is the question we asked: How often has each justice voted to strike down a law passed by Congress?

Declaring an act of Congress unconstitutional is the boldest thing a judge can do. That's because Congress, as an elected legislative body representing the entire nation, makes decisions that can be presumed to possess a high degree of democratic legitimacy. In an 1867 decision, the Supreme Court itself described striking down Congressional legislation as an act "of great delicacy, and only to be performed where the repugnancy is clear." Until 1991, the court struck down an average of one Congressional statute every two years. Between 1791 (the court's founding) and 1858, only two such invalidations occurred.