Guantanamo Bay detainees may not challenge their detention in American courts, a U.S. federal appeals court said Tuesday in a ruling upholding a key provision of a law at the centre of U.S. President George W. Bush's anti-terrorism plan.
  
The U.S. Court of Appeals for the District of Columbia Circuit ruled 2-1 that civilian courts no longer have the authority to consider whether the military is illegally holding foreigners.
  
Barring detainees from the U.S. court system was a key provision in the Military Commissions Act, which Bush pushed through Congress last year to set up a system to prosecute terrorism suspects.

The ruling is all but certain to be appealed to the Supreme Court, which last year struck down the Bush administration's original plan for trying detainees before military commissions.

The U.S. Justice Department said foreign enemy combatants are not protected by the American constitution.
(Andres Leighton/Associated Press)

The Military Commissions Act was crafted in response to that decision and the president hailed it as a necessary tool for bringing terror suspects to justice.

Civil libertarians and leading Democrats decried the law as unconstitutional and a violation of American values. The law allows the government to indefinitely detain foreigners who have been designated "enemy combatants" and authorizes the CIA to use aggressive but undefined interrogation tactics.

Attorneys argued law was unconstitutional

The most-criticized provision of the law stripped U.S. courts of the authority to hear arguments from detainees who said they were being held illegally.

Attorneys argued that the detainees aren't covered by that provision and that the law is unconstitutional.

"The arguments are creative but not cogent. To accept them would be to defy the will of Congress," Judge A. Raymond Randolph wrote.

U.S. citizens and foreigners being held inside the country normally have the right to contest their detention before a judge.

The Justice Department said foreign enemy combatants are not protected by the constitution.

Randolph and Judge David Sentelle ordered that the hundreds of cases pending in the lower courts be dismissed.

Judge Judith Rogers dissented, saying the cases should proceed.

"District courts are well able to adjust these proceedings in light of the government's significant interests in guarding national security," Rogers wrote.