Twenty-one German soldiers, including Lothar Eisentrager, (plaintiffs) were captured in China by the United States Army and convicted by an American military tribunal in China for participating in hostile military operations against the United States after Germany surrendered in World War II. The prisoners were returned to Germany to serve their prison sentences. The prisoners filed petitions for writs of habeas corpus in a United States federal district court against United States Secretary of Defense Louis Johnson and other United States military officials (defendants). The prisoners argued that their trials, convictions, and imprisonment violated the United States Constitution and the Geneva Convention’s standards concerning the treatment of prisoners of war. The district court denied the prisoners’ habeas petitions, but the court of appeals reversed. The United States Supreme Court granted certiorari.