The Roberts Court Justices already have revealed many differences from one another, but they also share a (possibly) significant commonality: Presidents promoted all of them to the U.S. Supreme Court from the U.S. Courts of Appeals. This means, of course, that they initially learned how to be judges while serving on a circuit court. How might the Justices' common route to the Court affect their actions on it? Social background theory hypothesizes that prior experience influences subsequent behavior such as voting, opinion writing, and coalition formation. This Article empirically analyzes promotion to the Supreme Court and examines the implications of promotion in light of the social background theory.