He is entitled to legal representation.
Remember your "Bill of rights"
He maybe guilty as sin, but is still entitled to a trial.
DJuqa,
A supreme court decision, artfully cited above by my friend JBerryhiil, covers this:
Ex Parte Quirin, 317 U.S. 1 (1942)…the law of war draws a distinction between the armed forces and the peaceful populations of belligerent nations and also between those who are lawful and unlawful combatants. Lawful combatants are subject to capture and detention as prisoners of war by opposing military forces. Unlawful combatants are likewise subject to capture and detention, but in addition they are subject to trial and punishment by military tribunals for acts which render their belligerency unlawful.
So the only question, again, is whether they are combatants or criminals, and whether these terrorist acts constitute a crime spree or warfare. In this case the Supreme Court unanimously supported trial by military tribunal, partly for the reasons I gave earlier.
This has been generally accepted throughout all previous wars in the US, except for the Richard Reid War and the Ibrahim Mousawi War, with which I am unfamiliar.