Document Type

Working Paper

Publication Date



United States v. Leon, probable cause, warrants, judicial behavior, search and seizure, good-faith exception, accountability, magistrate judges, exclusionary rule, empirical study of courts


This Article reports on a set of roughly thirty interviews with federal magistrate judges. The focus of the interviews was the impact of the Supreme Court case, United States v. Leon, on the behavior of magistrate judges. Leon, famously, put in place the "good faith" exception for faulty warrants that were obtained by the officers in good faith. The insertion of this exception diminished significantly the incentive for defendants to challenge problematic warrant grants. That effect, in turn, could have diminished the incentive for magistrate judge scrutiny of the warrants at the front end of the process. We do not find any indication of diminished scrutiny. What we do find, however, is a highly ritualized and formalistic process for the evaluation of warrants where calculations of probabilities are viewed through a legalistic rather than a pragmatic lens.

Library of Congress Subject Headings

Courts, Exclusionary rule (Evidence), Good faith (Law), United States magistrates, Responsibility, Warrants (Law), United States v. Leon, Searches and seizures, Judicial process