The U.S. Supreme Court and the Model of Contingent Discretion

Congress passes statutes defining particular areas of the law, but the Supreme Court can interpret those statutes. This tension over the meaning of the rule of law has profound implications for democratic theory and the separation of powers. Though scholars have examined whether the Supreme Court issues decisions against the preferences of Congress, there has been little focus on whether legislators can constrain the Court. Our study examines how much discretion Congress provides in statutes it enacts into law. Our basic argument is that ideological decision making by Supreme Court justices depends upon the level of discretion Congress incorporates into the law. The greater the discretion, the less constraint federal judges and justices will encounter, making them more likely to vote according to their individual ideologies. Conversely, more detailed statutes will reduce the judges' discretion. Using data on 1953-96 Supreme Court decisions, our analysis supports this model of contingent discretion.