Mohammed is the most valuable al-Qaida official in US custody and the central figure in a trial that will put the Pentagon's military tribunals under an intense spotlight. The tribunals have faced repeated legal setbacks, including a Supreme Court appeal on the rights of Guantanamo detainees that could produce a ruling this month halting the proceedings.

Defense attorneys harshly criticized the military commissions, which were declared unconstitutional by the Supreme Court in 2006 before being resurrected in an altered form by Congress and President Bush.

"I think the American people, if they ... understood the ramifications in the long term to our Constitution, to their Constitution, I think they would be ashamed," Lachelier said outside the heavily guarded courtroom.

The defense attorney tried to raise another pending Supreme Court decision in the courtroom, on the benchmark when defendants can be allowed to represent themselves, but Kohlmann told her to keep quiet.

"What part of 'no' do you not understand?" the judge said, peering down from the bench. "Sit down."

Binalshibh's civilian attorney, Thomas Durkin, said the men should be tried in US federal courts.

"We have had many terrorism cases in our federal court system," Durkin said, "I think it is a shame that for whatever reason the Bush administration has put on what we think is a show trial."

The military commissions plan to allow coerced testimony, although evidence obtained by torture is not allowed. Attorneys for Mohammed have said they will challenge evidence obtained through harsh interrogations.

Air Force Brig. Gen. Tom Hartmann, a top tribunal official, told reporters it was up to the judge to determine whether to allow as evidence statements obtained during waterboarding. Hartmann said waterboarding has not officially been classified as torture.