Eric, I think Joseph Heller would agree with the Catch-22 scenario you've described for the commissions at Guantanamo Bay. They truly are damned if they proceed and damned if they don't. Perhaps unintentionally, I think you've arrived at the right conclusion: The commissions are fundamentally and fatally flawed; the rule of law will prevail only if they are perpetually blocked. Specific evidence against defendants is irrelevant to the question of the tribunals' legitimacy, although I'd also argue that this evidence makes it all the more important that we find some way to try the men held at Gitmo.
Ironically, our French allies across the Atlantic might have found a way . A French court sentenced seven men to prison yesterday for aiding al-Qaida in Mesopotamia by funneling young Frenchmen to Iraq to wage war against U.S. and coalition forces there. French prosecutors brought this case in civilian court, using a combination of open and sealed (i.e., classified) evidence to prove the defendants' guilt in a six-day trial this past March. Now the defendants are headed for prison—and the French get to put points on the scoreboard in the fight against terrorism.
Maybe we can learn a thing or two from our colleagues in Paris?