The Myth of Fourth Amendment Scrutiny

The Supreme Court\u27s decision in Katz v United States made people\u27s reasonable expectations of privacy the touchstone for determining whether state surveillance amounts to a search under the Fourth Amendment. Ever since Katz, Supreme Court justices and numerous scholars have referenced the inherent circularity of taking the expectations-of-privacy framework literally: people\u27s expectations of privacy depend on Fourth Amendment law, so it is circular to have the scope of the Fourth Amendment depend on those same expectations. Nearly every scholar who has writ- ten about the issue has assumed that the circularity of expectations is a meaningful impediment to having the scope of the Fourth Amendment depend on what ordinary people actually expect. But no scholar has tested the circularity narrative\u27s essential premise: that popular sentiment falls into line when salient, well-publicized changes in Fourth Amendment law occur. Our Article conducts precisely such a test. We conducted surveys on census- weighted samples of US citizens immediately before, immediately after, and long after the Supreme Court\u27s landmark decision in Riley v California. The decision in Riley was unanimous and surprising. It substantially altered Fourth Amendment law on the issue of the privacy of people\u27s cell phone content, and it was a major news story that generated relatively high levels of public awareness in the days after it was decided. We find that the public began to expect greater privacy in the contents of their cell phones immediately after the Riley decision, but this effect was small and confined to the 40 percent of our sample that reported having heard of the decision. One year after Riley, these heightened expectations had disappeared completely. There was no difference from baseline two years after Riley either, with privacy expectations remaining as they were prior to the decision. Our findings suggest that popular privacy expectations are far more stable than most judges and commentators have been assuming. Even in the ideal circumstance of a clear, unanimous, and widely reported decision, circularity in Fourth Amendment attitudes is both weak and short lived. In the longer term, Fourth Amendment circularity appears to be a myth