The experience of World War II and the precedent of the Japanese American internment dramatically altered the political and legal landscape surrounding habeas corpus and suspension. This chapter discusses Congress’s enactment of the Emergency Detention Act of 1950 along with its repeal in 1971. It further explores how in the wake of the terrorist attacks of September 11, 2001, questions over the scope of executive authority to detain prisoners in wartime arose anew. Specifically, this chapter explores the Supreme Court’s sanctioning of the concept of the “citizen-enemy combatant” in its 2004 decision in Hamdi v. Rumsfeld and evaluates Hamdi against historical precedents. Finally, the chapter explores how Hamdi established the basis for an expansion of the reach of the Suspension Clause in other respects—specifically, to the U.S. Naval Base at Guantanamo Bay, Cuba.