Contemporary global crime and cross-border law enforcement cooperation have multiplied “foreign affairs prosecutions,” cases that encompass foreign apprehension, evidence gathering, and criminal conduct, as well as cases that implicate foreign nations’ criminal justice interests. Robert Mueller’s Russia investigation, the fugitive Edward Snowden, and the cross-border crimes of FIFA and El Chapo all exemplify such foreign affairs prosecutions. This Article argues that foreign affairs prosecutions represent a consequential shift in U.S. criminal law, offering the promise of closing global impunity gaps. At the same time, however, such cases risk defendant interests at home and U.S. foreign policy abroad. This Article calls for greater congressional engagement and judicial oversight to minimize such risks while still promoting accountability for cross-border, cyber, and international crime.