Detainees have the right to trial in US courts:

Prisoners have been detained at Guantanamo for long periods without clear charges being filed and without trial. This is a violation of the international legal principle of habeas corpus. One of the primary problems is that, without clear charges and a presentation of evidence against a suspect, the suspect cannot contest the charges and prove their own innocence. And, as a matter of fact, numerous detainees have been found innocent, but only after excessively long periods without being charged or brought before a court.[1] Many Guantanamo detainees may have never committed terrorist acts or fought against US forces in Afghanistan at all; they were simply turned over by Northern Alliance and Pakistani warlords for bounties of up to $25,000. For almost seven years they have been held without a fair hearing or opportunity to demonstrate those facts. Courts who reviewed the cases of 23 detainees to see if there was reasonable evidence for their continued detention found no credible basis for detaining 22 of them.[2] Other detainees were captured in places where, at the time of their arrest, there was no armed conflict involving US forces. The case of the six men of Algerian origin detained in Bosnia and Herzegovina in October 2001 is a well-known and well-documented example.[3] Therefore the only way to resolve these issues is to try all  the detainees at Guantanamo Bay in US courts, and release any against whom charges cannot be brought. Former US Secretary of Defense Colin Powell has endorsed this reasoning, arguing that "I would get rid of Guantanamo and the military commission system and use established procedures in federal law[...]It's a more equitable way, and more understandable in constitutional terms,"[4] US courts are fully capable of dealing with terrorist trials, as shown by the fact that they have rendered 145 convictions in terror-related cases in the past.[5] Convictions in US courts would probably be seen internationally as having more legitimacy than those obtained through the current system of military tribunals, which is often viewed as rigged against the defendants.[6] Only by allowing full due process in American courts can the rights of the detainees be uaranteed and their guilt or innocence truly established. [1] New York Times Opinion. "The President's Prison". New York Times. March 25, 2007. http://query.nytimes.com/gst/fullpage.html?res=9C06E6D71530F936A15750C0A... [2] Wilner, Thomas J. "We Don't Need Guantanamo Bay". Wall Street Journal. 22 December 2008. http://online.wsj.com/article/SB122990491721225253.html  [3] United Nations Economic and Social Council. "Economic, Social, and Cultural Rights. Civil and Political Rights. Situation of detainees at Guantánamo Bay". United Nations Economic and Social Council. February 15, 2006. [4] Reuters. "Colin Powell says Guantanamo should be closed". Reuters. 10 June 2007. http://www.reuters.com/article/2007/06/10/us-usa-powell-idUSN10436469200... [5] Wilner, Thomas J. "We Don't Need Guantanamo Bay". Wall Street Journal. 22 December 2008. http://online.wsj.com/article/SB122990491721225253.html  [6] Wilner, Thomas J. "We Don't Need Guantanamo Bay". Wall Street Journal. 22 December 2008. http://online.wsj.com/article/SB122990491721225253.html