Do political preferences change? A longitudinal study of US Supreme Court justices

Do the political preferences of U.S. Supreme Court justices change over time? Judicial specialists are virtually unanimous in their response: The occasional anomaly notwithstanding, most jurists evince consistent voting behavior over the course of their careers. Still, for all the research that presupposes the consistency of preferences, it is startling to find that scholars have yet to explore rigorously the assumption of stability. We fill this gap by describing the behavioral patterns of the 16 justices who sat on the U.S. Supreme Court for 10 or more terms, and began and completed their service sometime between the 1937 and 1993 terms. The data reveal that many experienced significant change over time-a result with important implications for virtually all longitudinal work on the Court.