It has been said that the surest way to become a federal judge is to first be a prosecutor. And it is generally perceived that a disproportionate number of federal judges served as government lawyers before donning a robe. Until now, however, no one had ever examined the professional background of every sitting federal judge to see whether that perception is true. In a new study, Cato scholar Clark Neily went through the federal judiciary judge by judge to test that perception.