My Amicus Brief in the Geofence Warrant Case, United States v. Chatrie

Yesterday, I submitted this brief as amicus curiae in United States v. Chatrie, the Supreme Court’s case on the Fourth Amendment implications of geofencing and geofence warrants.  You can get all of the briefs and materials in the case here. I’ll probably blog about the case over the next few weeks, but for now I just wanted to flag my amicus brief.  Here’s the Summary of Argument:

The challenge of new technology is a recurring theme in Fourth Amendment law. This case raises a host of new and important questions, and this brief hopes to help frame the issues and provide directions for answering them.

The first set of questions considers whether obtaining Chatrie’s Location History records was a Fourth Amendment “search” of his “papers.” There are two different arguments to evaluate. The first is the virtual private locker question. Did Chatrie store his Location History records in a virtual private locker with Google, such that he had Fourth Amendment rights in the contents of the virtual locker just as he would with an equivalent physical locker? This brief concludes that the answer is likely no. Although the record is murky on the point, Chatrie likely lacked the control over the records needed to have Fourth Amendment rights in them.

The second search argument considers whether Chatrie had Fourth Amendment rights under the limits placed on the third-party doctrine by Carpenter v. United States, 585 U.S. 296 (2018). This brief argues that he did not. Carpenter does not apply because Chatrie voluntarily opted in to have Google create and store his Location History records.

The next set of issues considers the lawfulness of the warrant, assuming that one was needed. The brief argues that a properly drawn geofence warrant can satisfy the Fourth Amendment. The Fourth Amendment does not present an all or nothing choice between zero protection and absolute protection. Where the law requires a warrant, it also provides a means to draft a lawful warrant.

On the specifics of the warrant in this case, the warrant was properly drawn as to Step 1 because it was sufficiently narrow in both time and space. The constitutionality of the warrant at Step 2 is uncertain, however. It is not clear that the Fourth Amendment allows multi-stage warrants, and the particularity of Step 2 debatable. Chatrie may not have raised these issues as to Step 2, however, so they may be waived.

The fact that this case reaches the Court so late in the Term, and that it raises so many complex issues, suggests that there may be value in pointing to a resolution that might plausibly reach consensus. If so, amicus suggests that the Court might want to resolve this case by focusing primarily on the warrant issues. The legality of the warrant implicates fewer contested questions and has a more complete factual record. For the sake of completeness, however, this brief covers both issues.