The U.S. Supreme Court ruled 5-4 in the case Boumediene v. Bush today that detainees at Guantanamo Bay have a right to bring habeas corpus cases in federal court. The habeas corpus jurisdiction stripping provisions of laws enacted by Congress to deny them this right (the Detainee Treatment Act and the Military Commissions Act) were held unconstitutional.
In another detainee case, Munaf v. Geren, the U.S. Supreme Court held unanimously, that the federal courts have habeas corpus jurisdiction over U.S. citizens held in military custody by U.S. soldiers in a military chain of command, even if they are part of a larger military coalition.
But the U.S. Supreme Court also held that on the merits in that U.S. citizens who travel voluntarily to a foreign country and are held there by U.S. military authorities may be transferred to the custody of local courts to face criminal charges arising from conduct in that country. No exception to this ruling on the merits exists even if the local courts don't meet U.S. constitutional standards and local authorities are alleged by authorities other than the U.S. Executive Branch to be likely to engage in torture in the particular case before a U.S. Court.
The later opinion involved U.S. citizens who voluntarily traveled to Iraq and faced indictment by Iraqi courts for offenses committed in Iraq. Thus, this leaves open the more general question of the legality on the merits of extraordinary rendition of U.S. citizens to countries whom third parties claim engage in torture. The question of whether the U.S. military may transfer someone to foreign authorities whom it openly agrees are likely to torture the person transferred also remains unresolved.
These cases also leave open the jurisdiction of U.S. courts in habeas cases involving people who aren't U.S. citizens in places, unlike Guantanamo Bay, where the U.S. does not have de facto sovereign authority, although the Guantanamo Bay case made clear that the proper analysis hinges on the objective reality and practicalities involved, rather than legal formalities like sovereignty. The Guantanamo Bay case also suggested that a government intent to evade habeas corpus jurisdiction by its actions was a factor to be considered, and that an intent to evade habeas corpus jurisdiction hurts the government's case.
The scope of habeas review is unclear. But it appears that detainees will be allowed a full evidentiary hearing in a federal courts with the power to release them from custody on the questions of whether the detainee is indeed an enemy combatant, and on the question of whether the President had the legal authority to detain the detainee given the findings of fact made in the federal court. The Combat Status Review Tribunals currently in place to make enemy combatant determinations were found by the U.S. Supreme Court to be constitutionally inadequate.
The ruling leaves in tact provisions of the Military Commissions Act establishing an amnesty for U.S. government officials who committed war crimes during the Bush Administration from civil and criminal liability, and a prohibition on entertaining civil actions of detainees other than habeas corpus petitions in connection with their detentions.
While the rulings have no direct impact on the military commission trials of a couple dozen detainess for war crimes, legal commentators have suggested that the ruling may enlarge the scope of legal arguments that counsel for the detainees may make before those Commissions by clarifying that U.S. Constitutional protections apply to detainees at Guantanamo Bay. For example, detainees in custody prior to the enactment of the Military Commissions Act may be allowed to argue that under the Ex Post Facto clause, they may not be tried for crimes like conspiracy, which were not considered war crimes prior to the enactment of the Military Commissions Act. The admissibility of evidence based upon coerced testimony (i.e. torture) may also be in doubt. And, this ruling probably spares Omar Khadr from the possibility of the death penalty, because he was a juvenile at the time that the alleged war crimes were committed.