A Game Theory Model of the Supreme Court

January 17th, 2012

From A Dynamc Model of Doctrinal Choice:

This paper develops a repeated game model of the choice of doctrinal form by a higher court. Doctrine can take any point along a continuum from more determinate, rule-like legal commands to more flexible, standard-like directives. In deciding a case, the Supreme Court not only decides on a substantive outcome, but also chooses where on this continuum to set the doctrine. The lower court then applies the legal command to future cases. In doing so, it may wish to take into account new information, but the cost of doing so varies with the form of the legal doctrine. The model shows that in equilibrium doctrine oscillates over time between more rule-like commands and more standard-like commands. What triggers the shift in doctrinal form are the lower court’s “mistakes” when trying to implement the standard in the way the Supreme Court prefers. The mistakes induce the Supreme Court to cabin the lower court’s discretion by issuing more rule-like legal commands for a certain number of periods. Too much constraint, however, produces error costs when the lower court cannot adjust the law appropriately to new circumstances, leading to a shift back to more standard-like doctrine. We derive comparative statics showing how the length of the constraint phase responds to the degree of preference conflict between the courts. Finally, we illustrate the features of the model through a doctrinal case study of the law governing the voluntariness of confessions.