An Examination of the Coherence of Fourth Amendment Jurisprudence

Abstract

For decades, scholars have routinely attacked the Supreme Court’s Fourth Amendment jurisprudence as an incoherent mess, impossible for lower courts to follow. These scholars have based their claims almost entirely on qualitative analysis of the Court’s opinions. This article presents the first systematic evaluation of the consensus view of Fourth Amendment law as incoherent. The primary method I use to evaluate the coherence of the body of law is an assessment of lower court performance on Fourth Amendment issues the Supreme Court would later resolve. Because the Supreme Court’s agreement with lower courts likely reflects, at least in part, the clarity of the Supreme Court’s previous pronouncements, a high rate of agreement between lower courts and the Supreme Court would tend to suggest the coherence of the field. I examine lower court decisions dealing with issues the Supreme Court subsequently addressed over the course of twenty Supreme Court terms. Because Supreme Court cases tend to deal with the most difficult, divisive issues, I also compare the frequency with which the Court has felt compelled to review Fourth Amendment questions to the rate at which the Court has dealt with other important constitutional issues.In addition to tracking the performance of lower courts, I track variables that might impact the likelihood of lower courts reaching “right” answers to Fourth Amendment questions. Because the process the Court uses to resolve a case gives clues about the kind of guidance the Court has previously provided on an issue, I account for whether the Supreme Court used open-ended balancing or a more constrained form of analogical reasoning from precedent to resolve each case in the data set. I also assess whether the directive the Court issued for each case took the form of a bright-line rule or an open-ended standard. Finally, because several scholars have recommended reference to positive law as a means of clarifying Fourth Amendment law, I evaluate the Court’s reliance on positive law to resolve Fourth Amendment questions during the twenty-year period.Ultimately, the results show that lower courts have reached the “right” answers to Fourth Amendment questions about as often as lower courts have reached the “right” answers to all questions the Supreme Court later reviews. Furthermore, the Court has not felt compelled to resolve Fourth Amendment questions at a rate that seems disproportionate to other important constitutional matters. These data point toward the plausible conclusion that Fourth Amendment law is not particularly incoherent, as compared with other areas of law. Examination of the Court’s use of positive law reveals that the Court has, for the most part, not relied on positive law in ways likely to enhance significantly the coherence of Fourth Amendment law. Thus, a more principled approach to using positive law to resolve Fourth Amendment questions might increase the coherence of the field. Finally, analysis of the data suggests the Court should issue directives in the form of bright-line rules instead of open-ended standards if it hopes further to enhance the clarity of Fourth Amendment law.