Military Commissions Act — Trying Enemy Combatants Outside Federal Court

When the United States captured Taliban and al-Qaeda fighters after September 11, 2001 and held them at Guantanamo Bay (see Habeas Corpus for the detention review framework), Cuba, a fundamental legal question arose: could these detainees be tried by military tribunal rather than in federal civilian court, and under what rules? The answer came in a series of Supreme Court decisions, presidential orders, and ultimately two acts of Congress: the Military Commissions Act of 2006 (MCA 2006) and the Military Commissions Act of 2009 (MCA 2009). Together, these laws established a specialized legal system within the Department of Defense for trying noncitizen enemy combatants for war crimes and terrorism-related offenses. The system operates under the UCMJ's framework but with its own rules of evidence, its own appellate court, and its own list of triable offenses. Military commissions have tried only a handful of defendants — the Guantanamo case backlog remains largely unresolved more than two decades after 9/11 — but the legal framework they created reflects profound questions about how a constitutional democracy wages war against non-state actors who don't wear uniforms or represent a country.

Current Law (2026)

Legal Authority

• 10 U.S.C. § 948a — Definitions: "alien unprivileged enemy belligerent" means a person who (1) has engaged in hostilities against the U.S. or its coalition partners, or (2) has purposefully and materially supported such hostilities; and who is neither a U.S. citizen nor entitled to be treated as a lawful combatant under the laws of war
• 10 U.S.C. § 948b — Military commissions generally: the President may establish military commissions to try noncitizen enemy belligerents for violations of the law of war and other offenses triable by commission under the chapter; the commissions are not governed by the Uniform Code of Military Justice but are established within the UCMJ framework
• 10 U.S.C. § 948c — Jurisdiction: military commissions have jurisdiction to try alien unprivileged enemy belligerents for offenses listed in §950t; jurisdiction exists regardless of where the offense was committed or when (no statute of limitations for these offenses)
• 10 U.S.C. § 948r — Exclusion of coerced statements: any statement obtained by torture is inadmissible; any statement obtained by cruel, inhuman, or degrading treatment (as defined by the Detainee Treatment Act) is inadmissible; other statements taken in violation of the DTA may be admitted if the military judge determines they are reliable, probative, and admission is in the interests of justice
• 10 U.S.C. § 949d — Sessions: the military judge may close proceedings to protect classified information or witnesses; certain evidence may be provided in summaries or by redaction to protect national security
• 10 U.S.C. § 950b — Review by convening authority: after sentencing, the convening authority reviews the record and approves or modifies findings and sentences; may disapprove a conviction in whole or part; cannot increase a sentence
• 10 U.S.C. § 950f — Court of Military Commission Review: a new Article III-equivalent court established within DOD to hear appeals from military commissions; decisions are subject to appeal to the D.C. Circuit Court of Appeals
• 10 U.S.C. § 950g — D.C. Circuit review: the United States Court of Appeals for the D.C. Circuit is the only federal appellate court for final review of military commission decisions; certiorari may be sought in the Supreme Court
• 10 U.S.C. § 950t — Crimes triable by military commission: 32 specific offenses, including: terrorism; murder of protected persons; taking hostages; attacking civilian objects; using treachery; murder in violation of the laws of war; torture; cruel treatment; use of poison or analogous weapons; using protected persons as shields; material support for terrorism; conspiracy; solicitation; hijacking; destruction of property; spying; providing false statements

Who Can Be Tried

The MCA covers only "alien unprivileged enemy belligerents" — noncitizens who have engaged in or materially supported hostilities against the U.S. U.S. citizens cannot be tried by military commission under the MCA; they must be charged in federal civilian courts or under the UCMJ if they are service members.

The "material support for terrorism" offense (§950t(25)) has been among the most litigated provisions. The D.C. Circuit Court of Appeals vacated convictions of Guantanamo detainees who were charged only with material support for terrorism, holding that this offense did not constitute a recognized war crime under international law as of the time of the alleged conduct. The legal status of material support charges before military commissions remains unsettled.

Key Procedural Features

Evidence rules in military commissions are more flexible than in federal court. Hearsay evidence may be admitted if the military judge determines it has "sufficient probative value and reliability." The confrontation rights of defendants with respect to classified evidence are limited — defendants may receive unclassified summaries of classified evidence rather than the evidence itself.

Classified evidence is a central challenge. The Classified Information Procedures Act (CIPA) governs classified evidence in civilian courts — see Espionage Act & Classified Information for the broader framework. In military commissions, similar but distinct rules apply. The military judge must balance the defendant's right to confront evidence against the government's interest in protecting intelligence sources and methods. Some prosecutions have stalled for years over classified evidence disputes.

Defense rights: Defendants are entitled to military defense counsel and may also retain civilian counsel at their own expense. The military judge must ensure that the defendant understands the charges. Double jeopardy protections apply (§949h).

The Boumediene v. Bush Decision

The Supreme Court's 2008 decision in Boumediene v. Bush fundamentally changed the legal landscape for Guantanamo detainees. The Court held that detainees held at Guantanamo Bay have the constitutional right to habeas corpus under the Suspension Clause of Article I, §9 — the right to challenge their detention in federal court. MCA 2006 had stripped federal courts of habeas jurisdiction over Guantanamo detainees, and the Court found this unconstitutional. As a result, Guantanamo detainees can file habeas petitions in federal district courts in Washington, D.C., challenging the factual basis for their detention. This right to habeas review is separate from the appellate review of military commission convictions.

The Guantanamo Situation

The military commissions system has produced a small number of completed prosecutions despite being in operation since 2006. The flagship case — the prosecution of Khalid Sheikh Mohammed and four others for the September 11 attacks — remained in the pre-trial phase as of 2026, with legal challenges to evidence obtained by "enhanced interrogation techniques" and classified evidence disputes generating years of delay. Several convictions have been vacated or modified on appeal, including the landmark ruling that material support for terrorism was not a recognized law of war offense at the time of the alleged conduct.

How It Affects You

If you're a defense attorney, military defense counsel, or legal scholar, military commissions represent one of the most legally exotic and contested areas of U.S. law — a hybrid system that intersects international laws of war, constitutional due process, national security evidence law, and UCMJ military justice. The system has its own definitions, its own evidence rules (more permissive than federal court — hearsay may be admitted; confrontation rights are limited for classified evidence), its own appellate structure (CMCR → D.C. Circuit → Supreme Court), and its own list of 32 triable offenses under § 950t. Key doctrinal landmarks: Boumediene v. Bush (2008) held that Guantanamo detainees have constitutional habeas corpus rights despite not being on U.S. soil, invalidating the MCA 2006 jurisdiction-stripping provision; D.C. Circuit decisions vacated material support convictions for pre-statute conduct, leaving the scope of triable offenses uncertain. If you're practicing in this space, the Center for Constitutional Rights (ccrjustice.org) and the Military Commissions Defense Organization (Defense Department's dedicated military defense counsel for Guantanamo cases) maintain the most current procedural documentation. For evidence classification questions, the Classified Information Procedures Act (CIPA) governs parallel civilian contexts but commissions have their own classified evidence rules.

If you work in national security policy, counterterrorism, or government service, the military commissions system's practical track record is a central fact in any honest assessment: after 20+ years of operation and billions in costs, the flagship September 11 prosecution has still not gone to trial as of 2026, while federal civilian courts have successfully prosecuted hundreds of terrorism cases to final judgment. The federal system convicted Zacarias Moussaoui, the "20th hijacker," in 2006; convicted Sulaiman Abu Ghayth (bin Laden's son-in-law) in 2014; and has disposed of numerous terrorism cases through plea agreements and trials. The argument for military commissions — that classified evidence and the law-of-war framework fit terrorist combatants better than civilian procedures — has not been validated by the commissions' performance. The argument against — that the system's constitutional tenuousness, evidence admissibility fights, and endless appellate litigation create more delay than civilian courts would — has more empirical support. For future terrorism cases, the venue decision (civilian federal court vs. military commission) is primarily a policy and political question given the constitutional constraints that Boumediene established. Track current Guantanamo case status through the Office of Military Commissions at mc.mil and the Lawfare blog (lawfaremedia.org) for comprehensive legal analysis.

If you're a voter, taxpayer, or concerned citizen, the Guantanamo detention and military commission system is a durable national security policy dilemma that has outlasted four presidents. The annual cost of operating Guantanamo has been estimated at $13 million per detainee per year — compared to approximately $40,000–$60,000/year to incarcerate someone in a federal maximum-security prison. The Guantanamo population has declined from a peak of approximately 780 detainees to fewer than 30 as of 2026; most detainees have been transferred to other countries without criminal charges. Congressional restrictions bar the transfer of Guantanamo detainees to the U.S. mainland for prosecution or detention, which has effectively blocked closure attempts and created the indefinite detention status that ongoing habeas litigation challenges. The unresolved September 11 cases — Khalid Sheikh Mohammed and four co-defendants — represent the most significant pending criminal matter related to the worst terrorist attack in U.S. history. Whether justice in these cases will ever be delivered through the military commissions system — or whether a different legal framework was always needed — is the central question hanging over the entire 25-year experiment.

State Variations

Military commissions are exclusively federal law. State criminal law does not apply.

Pending Legislation

Congress periodically considers legislation related to Guantanamo closures, the transfer of detainees, and modifications to the military commissions framework. Restrictions on transferring Guantanamo detainees to the United States have been included in annual defense authorization acts, preventing trials in civilian courts within U.S. territory. No comprehensive resolution of the Guantanamo situation has been enacted as of 2026.

Recent Developments

Pre-trial proceedings in the September 11 cases continued through 2026, with repeated delays caused by defense challenges to the competency of the judge, challenges to evidence derived from CIA enhanced interrogation, and classified evidence disputes. The Biden administration's efforts to negotiate plea agreements in some cases generated congressional controversy. The CMCR issued several significant rulings on the scope of triable offenses and evidentiary standards. The fundamental question of whether Guantanamo detainees can ever be given fair trials under the commissions framework — or whether civilian federal prosecution was always the more effective approach — remains unresolved.