Marty Lederman makes a good point here: Calls to shut down the military detention camp at Guantanamo are all well and good, but we want to make sure that if it ever does close that the prisoners won't get transferred to something even worse. Lederman suggests preserving Guantanamo, but actually bringing it under the rule of law and then transferring all the prisoners held in the CIA's "secret prisons" to Guantanamo. That would be better than the status quo, certainly, although Guantanamo is probably too notorious as a symbol of American human rights violations to stay open, period.
It also goes without saying that the Bush administration simply isn't going to bring its vast network of prisons under the rule of law anytime soon. One problem with the fact that the U.S. has been abusing a bunch of "suspects" in its custody is that, as Philip Carter argued, whatever evidence they may have offered up under torture is inadmissible in court. And that could make it harder to prosecute a number of terrorist suspects:
Evidence (such as a confession) gathered as a result of torturing a person like [alleged 9/11 mastermind Khalid Sheik] Mohammed will be excluded at his trial, if he ever sees one. This is true both in federal courts, which operate under the Federal Rules of Evidence, and military courts, which operate under the Military Rules of Evidence. Both the Fifth Amendment's right against compulsory self-incrimination and the 14th Amendment's guarantee of due process preclude the use of a defendant's coerced statement against him in criminal court.
In addition, any evidence gathered because of information learned through torture (sometimes called "derivative evidence") will likely also be excluded. Furthermore, the Supreme Court suggested in its landmark Fifth Amendment case, Oregon v. Elstad, that it might exclude evidence gathered after the use of any coercion, regardless of attempts by police and prosecutors to offset the coercion with measures like a Miranda warning. If Mohammed were prosecuted, and a court followed the line of reasoning set forth in Elstad, he might well see the charges against him evaporate entirely for lack of evidence.So unless the federal government wants to face the possibility that Mohammed could be set free, it might have to keep him in some sort of extralegal detention center well, forever. (Carter suggests that the Bush administration could still, potentially, bring al-Qaeda suspects before military tribunals and avoid this problem, but even that's not clear.)