[JURIST] Wire services are reporting that the US Supreme Court [official website] has ruled that military commissions [DOD materials] at Guantanamo Bay are illegal under military law and the Geneva Conventions [ICRC materials], holding in Hamdan v. Rumsfeld [Duke Law case backgrounder; JURIST news archive], that President Bush did not have authority to establish the commissions as constituted.

Salim Hamdan [Trial Watch profile], a former driver for Osama bin Laden who is being held at Guantanamo Bay [JURIST news archive], challenged his trial before a military commission [JURIST news archive] rather than in front of an ordinary military court. Hamdan's lawyer told the Court during oral arguments [recorded audio; JURIST report] in March that the commission system is unfair because it allows President Bush's military subordinates to determine who will act as judge and jury and also decide which crimes will be prosecuted. The Bush administration argued that the special military tribunals established by the president [Military Order text], which do not adhere to either standard US military procedure or the Geneva Conventions, can be used to prosecute suspected terrorists as war criminals. The government has said that Hamdan is not entitled to Geneva Convention protections because he was not part of a uniformed enemy.

10:27 AM ET – The decision was 5-3, with Chief Justice Roberts not participating as he had previously ruled on the case in favor of the government [opinion text; JURIST report] while sitting as a judge on the US DC Circuit Court of Appeals. SCOTUSblog has more.

11:29 AM ET – The Court held there is no express authorization from Congress for Hamdan's military commission and that commission structures and procedures violate both the Uniform Code of Military Justice [text] and the Geneva Conventions. The Court said that commission procedures set forth in Commission Order No. 1 [PDF text] do not comply with UCMJ Article 36 [text]. The statute allows military commission procedures to differ from standard criminal procedure or military court-martial rules when necessary, but the Court ruled that although the President has determined that it is impracticable to apply "the principles of law and the rules of evidence generally recognized in the trial of criminal cases in the United States district courts," he has not "made a similar official determination that it is impracticable to apply the rules for courts-martial." The Court also said:

Nothing in the record before us demonstrates that it would be impracticable to apply court-martial rules in this case. There is no suggestion, for example, of any logistical difficulty in securing properly sworn and authenticated evidence or in applying the usual principles of relevance and admissibility. Assuming arguendo that the reasons articulated in the President's Article 36(a) determination ought to be considered in evaluating the impracticability of applying court-martial rules, the only reason offered in support of that determination is the danger posed by international terrorism.52 Without for one moment underestimating that danger, it is not evident to us why it should require, in the case of Hamdan's trial, any variance from the rules that govern courts-martial.

The absence of any showing of impracticability is particularly disturbing when considered in light of the clear and admitted failure to apply one of the most fundamental protections afforded not just by the Manual for Courts-Martial but also by the UCMJ itself: the right to be present. See 10 U. S. C. A. §839(c) (Supp. 2006). Whether or not that departure technically is "contrary to or inconsistent with" the terms of the UCMJ, 10 U. S. C. §836(a), the jettisoning of so basic a right cannot lightly be excused as "practicable."

Under the circumstances, then, the rules applicable in courts-martial must apply. Since it is undisputed that Commission Order No. 1 deviates in many significant respects from those rules, it necessarily violates Article 36(b).

With respect to the Geneva Conventions, the Court held that Article 3 [text] – often called Common Article 3 as it is common to all four Geneva Conventions – applies even though the US is at war with al Qaeda, which is not a signatory to the conventions. The Court said:

Common Article 3, then, is applicable here and, as indicated above, requires that Hamdan be tried by a "regularly constituted court affording all the judicial guarantees which are recognized as indispensable by civilized peoples." 6 U. S. T., at 3320 (Art. 3, ¶1(d)). While the term "regularly constituted court" is not specifically defined in either Common Article 3 or its accompanying commentary, other sources disclose its core meaning. The commentary accompanying a provision of the Fourth Geneva Convention, for example, defines "'regularly constituted'" tribunals to include "ordinary military courts" and "definitely exclud[e] all special tribunals." GCIV Commentary 340 (defining the term "properly constituted" in Article 66, which the commentary treats as identical to "regularly constituted");64 see also Yamashita, 327 U. S., at 44 (Rutledge, J., dissenting) (describing military commission as a court "specially constituted for a particular trial"). And one of the Red Cross' own treatises defines "regularly constituted court" as used in Common Article 3 to mean "established and organized in accordance with the laws and procedures already in force in a country." Int'l Comm. of Red Cross, 1 Customary International Humanitarian Law 355 (2005); see also GCIV Commentary 340 (observing that "ordinary military courts" will "be set up in accordance with the recognized principles governing the administration of justice").

The Government offers only a cursory defense of Hamdan's military commission in light of Common Article 3. See Brief for Respondents 49-50. As Justice Kennedy explains, that defense fails because "[t]he regular military courts in our system are the courts-martial established by congressional statutes." Post, at 8 (opinion concurring in part). At a minimum, a military commission "can be 'regularly constituted' by the standards of our military justice system only if some practical need explains deviations from court-martial practice." Post, at 10. As we have explained, see Part VI-C, supra, no such need has been demonstrated here.65 …

Common Article 3 obviously tolerates a great degree of flexibility in trying individuals captured during armed conflict; its requirements are general ones, crafted to accommodate a wide variety of legal systems. But requirements they are nonetheless. The commission that the President has convened to try Hamdan does not meet those requirements.

The Court also refused to grant the government's motion to dismiss [PDF text; JURIST report] the case based on the Detainee Treatment Act [JURIST document], part of which limits the ability of Guantanamo prisoners to challenge their detentions in federal courts, saying that Congress did not intend for the relevant DTA provision to apply to pending claims. The Court also specifically noted that it was not addressing "the Government's power to detain [Hamdan] for the duration of active hostilities in order to prevent such harm."

Read the Court's opinion [text] per Justice Stevens, along with a concurrence [text] from Justice Breyer, who was joined by Justices Kennedy, Souter and Ginsburg; a concurrence in part and dissent in part [text] from Justice Kennedy, who was joined in part by Justices Souter, Ginsburg and Breyer; a dissent [text] from Justice Scalia, who was joined by Justices Thomas and Alito; a dissent [text] from Justice Thomas, who was joined in full by Justice Scalia and in part by Justice Alito; and a final dissent [text] from Justice Alito, who was joined in part by Justices Scalia and Thomas.

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