In Millard v. Camper, — F.3d — , 2020 WL 4875290 (10th Cir. 2020), the Tenth Circuit reversed an unprecedented ruling in which the district court had held Colorado's sex offender registration act to be unconstitutional on multiple grounds. Following both Supreme Court and Tenth Circuit precedent, the circuit court rejected plaintiffs' as-applied constitutional challenges based on cruel and unusual punishment and substantive due process. The court also overturned the lower court's ruling that one plaintiff had been deprived of procedural due process by state courts, because the federal district court lacked appellate jurisdiction under the Rooker-Feldman doctrine to hear a challenge to those state-court decisions.