The focus of this investigation is the relationship of the United States Supreme Court's functional performance to its environment. Three functions of courts are noted in the literature: conflict resolution, social control and administration. These functions are operationalized for the United States Supreme Court. Hypotheses are developed relative to the general performance of these three functions by all courts. Box-Jenkins time series analysis is then used to test these hypotheses in relation to the performance of the United States Supreme Court. The primary analysis rests upon a data set that includes all non-unanimous decisions of the Supreme Court from 1916 to 1986. A supplemental analysis is conducted using all formal decisions for the 1953 to 1986 period. The results suggest that intellectual resources, legal resources, modernization, and court discretion are significant influences on the functional performance of the United States Supreme Court. Future research must consider these influences in the development of a general theory of courts.