To say that a constitutional court has played a significant role in governance of a nation implies that the court's decisions are consequential – that they make a difference, have an independent effect on politics, public policy, and power relationships, or on social or economic life, the treatment of minorities, criminal suspects, political or religious dissidents. This essay, accordingly, discusses the roles played by the U.S. Supreme Court in the twentieth century, asking to what extent and in what ways the Court was a consequential political actor.
Lawyers and legal scholars take it for granted that the U.S. Supreme Court, which has exercised the power of constitutional judicial review for more than 200 years, has been a politically consequential court. To many political scientists, however, the Court's actual influence is an unsettled empirical and theoretical question. Scholars often referred to as regime theorists argue that constitutional courts only rarely, if ever, have a powerful independent effect on government and society (Dahl, 1957; Rosenberg, 1991; Peretti, 1999; Pickerell & Clayton, 2004; Whittington, 2008). Regime theorists see high courts not primarily as politically powerful principals but as agents whose decisions in politically significant cases generally reflect the preferences of the political leaders who appointed them. Even if judges are personally inclined to make bold, politically unpopular rulings, it is argued, prudence usually impels them to act strategically, avoiding decisions that important political leaders are likely not only to denounce but to resist, reverse, or retaliate against (Epstein, Knight, & Shvetsova, 2001). In this view, therefore, when judicial decisions do have broad social or political consequences, it is because powerful political leaders or parties approve of (or at least accept) those decisions and – just as importantly – are willing to implement them. In regime theory, the judges may appear to be the engineer driving the legal or constitutional train, but political leaders have built the track and selected the engineers, thus deciding what direction they want the train to go.