542 U.S. 507 (2004) (U.S. Supreme Court)
Hamdi v. Rumsfeld is a foundational post-9/11 case at the intersection of separation of powers, due process, and national security.
Does the Executive have authority to detain a U.S. citizen as an enemy combatant under the AUMF, and if so, what process does the Due Process Clause require for the citizen-detainee to challenge that classification via habeas corpus?
Detention of enemy combatants for the duration of hostilities is a fundamental incident of waging war and is authorized for individuals who were part of or supported forces hostile to the United States in Afghanistan and who engaged in armed conflict against the United States there. Although Congress's AUMF constitutes authorization to detain within this narrow category and thereby satisfies 18 U.S.C. § 4001(a) (the Non-Detention Act) according to the plurality, a citizen-detainee seeking habeas review must receive notice of the factual basis for his enemy-combatant designation and a fair opportunity to rebut the government's factual assertions before a neutral decisionmaker. Applying Mathews v. Eldridge, the procedures may be tailored to the exigencies of war, including acceptance of hearsay, use of a rebuttable presumption in favor of the government's evidence, and burden-shifting, but they must provide a meaningful opportunity to contest the detention.
A plurality concluded that the AUMF authorizes the detention of a U.S. citizen captured in Afghanistan as an enemy combatant, but a majority held that due process requires that the citizen-detainee be given notice of the factual basis for his classification and a fair opportunity to rebut the government's evidence before a neutral decisionmaker through habeas proceedings. The Fourth Circuit's highly deferential approach was rejected, and the case was remanded for proceedings consistent with these requirements.
Hamdi is a cornerstone case for understanding how constitutional protections operate in wartime. It confirms that federal courts retain habeas jurisdiction to review executive detention decisions, even during authorized hostilities, and that due process applies to citizens designated as enemy combatants. The decision operationalizes Mathews v. Eldridge in the national security context, approving flexible yet real procedures that ensure a meaningful opportunity to contest detention. For students, Hamdi illustrates statutory interpretation of the AUMF against the Non-Detention Act, separation-of-powers constraints on the Commander in Chief, and how fractured opinions can still yield a controlling rule on process. The case also set the stage for later detainee litigation by establishing that security and liberty are not mutually exclusive: Congress may authorize wartime detention, but the Constitution demands judicially reviewable safeguards.