According to the NYT, the White House is trying to bypass the Supreme Court's ruling in the Hamdan case that Guantanamo detainees are entitled to the protection of the Geneva Convention.
Jack Balkan says:
" It allows detainees to be excluded from their own trials and it states that the Geneva Conventions "are not a source of judicially enforceable individual rights." Although it bans the introduction of statements obtained through "torture", it allows introduction of statements made under "coercion" (i.e., anything the Administration regards as less than torture-- which turns out to be a wide array of forms of prisoner mistreatment) unless a military judge finds that the evidence would be "unreliable." It is no accident, then, that the draft demands that Common Article 3 of the Geneva Conventions not be judicially enforceable...
Much of the American public probably cares more about their privacy being violated by domestic surveillance than about the rights of detainees at Guantanamo, which suggests that Congress would be more likely to give in here. However, in the case of military tribunals, unlike the NSA case, the Supreme Court has declared the President's plan illegal."