The U.S. Court of Appeals for the D.C. Circuit Tuesday ruled that Guantanamo Bay detainees do not have a right to petition for habeas corpus, letting stand a key piece of the Military Commissions Act passed by Congress late last year.

The 2-1 decision was sharply critical of the plaintiffs, who had argued that the language of the act forbidding U.S. courts to hear challenges to the detention of aliens detained as enemy combatants was ambiguous and did not necessarily apply to detainees whose cases were already pending in court.