Hamdi v. Rumsfeld (2004)
The Court ruled that the executive branch alone does not have the power to designate people as “enemy combatants” and then use that designation as a reason to hold them indefinitely without due process. “A state of war is not a blank check for the President when it comes to the rights of the Nation’s citizens.” The Constitution’s separation of powers requires that courts review presidential decisions.
However, a plurality of justices agreed that Congress had authorized Hamdi’s detention when it approved the use of force in Afghanistan. Therefore, the government had the power to detain him as long as the war continued.