Abstract
In late 2016, U.S. Court of Appeals for the Sixth Circuit’s concluded in Does #1–5 v. Snyder that Michigan’s sex offender registry and residency re-striction law constituted an ex post facto punishment in violation of the constitu-tion. In its decision, the Sixth Circuit engaged with scientific evidence that re-futes moralized judgments about sex offenders, specifically that they pose a unique and substantial risk of recidivism. This Essay is intended to highlight the importance of Snyder as an example of the appropriate use of scientific studies in constitutional law.