Ex parte Milligan civilian trial

Facts of the Case

Petitioner prisoner was arrested and confined in a military prison. At trial, the prisoner objected to the authority of the military commission to try him, but he was sentenced to death. He filed a petition for discharge from unlawful imprisonment in the Circuit Court of the United States for the District of Indiana. The prisoner argued that the military commission did not have jurisdiction to try him.


“(1) Does an arrest violate the Fourth Amendment when a police officer has probable cause to make an arrest for one offense, if that offense is not closely related to the offense articulated by the officer at the time of the arrest? (2) For the purposes of qualified immunity, was “closely related offense doctrine” clearly established given that different circuit courts disagreed on its application?”


Writing for the Court, Justice David Davis held that trials of civilians by presidentially created military commissions are unconstitutional. Specifically, it is unconstitutional to try civilians by military tribunals unless there is no civilian court available. The military commission therefore did not have jurisdiction to try and sentence Milligan, and he was entitled to discharge.

Case Information

Citation: 71 US 2 (1866)
Argued: Mar 10, 1866