We lack consensus regarding who lawfully may be held in military custody in the contexts that matter most to U.S. national security today—- i.e., counterterrorism and counterinsurgency. More to the point, federal judges lack consensus on this question. They have grappled with it periodically since 2002, and for the past three years have dealt with it continually in connection with the flood of habeas corpus litigation arising out of Guantanamo in the aftermath of the Supreme Court’s 2008 decision in Boumediene v. Bush. Unfortunately, the resulting detention jurisprudence is shot through with disagreement on points large and small, leaving the precise boundaries of the government’s detention authority unclear. The aim of this Article is to flesh out and contextualize these disagreements, and to locate them in relation to larger trends and debates.