Herman Gundy (defendant) pled guilty to sexually assaulting a child in 2005. The next year, Congress enacted the Sex Offender Registration and Notification Act (SORNA), imposing a uniform national registration system for all sex offenders, including those convicted before SORNA’s passage. Congress delegated “the authority to specify the applicability” of the registration requirements to pre-act offenders to the United States attorney general (AG). After his release from prison, Gundy lived in New York without registering there as a sex offender and was convicted for failing to register a few years later. Gundy appealed on multiple grounds, including an argument that Congress could not constitutionally delegate authority to the AG to decide SORNA’s applicability to pre-act offenders. The Supreme Court granted review of the issue.