Abstract: This paper investigates rational choice explanations for patterns of Supreme Court decision-making with respect to the appropriate level of judicial deference to administrative agency decisions. In particular, I assess empirically the thesis that the Supreme Court expands deference when the Supreme Court is ideologically closer to the executive than to the circuit courts, and contracts deference when the opposite is true. I find little to no evidence supporting this "rational choice" theory of judicial deference. Given this surprising null finding, I offer alternative explanations for the data and suggest directions for future research.