Hamdi v. Rumsfeld (2004)
Yaser Hamdi was an American citizen who was captured by a militia in Afghanistan in the fall of 2001 and turned over to the US military.  He was then sent to a military prison on a naval ship in South Carolina , where he was held incommunicado an "unlawful enemy combatant" without access to a lawyer or the courts.   A Virginia attorney challenged his indefinite detention by filing a habeas corpus petition on his behalf, and a US District Court agreed that there was no good evidence to hold him without access to the courts.  But a panel of the US Appeals Court for the Fourth Circuit found that the executive branch could hold him indefinitely because he had been captured in a "zone of active combat" and that he did not have the right to a court hearing.  The US Supreme Court disagreed.  With Justice Sandra Day O'Connor writing the opinion, the court said that an "enemy combatant" who was a US citizen did have the Fifth Amendment right to appear before a judge or "neutral decision-maker."  Rather than bring Hamdi to court, the Bush Administration stripped him of his US citizenship and deported him to Saudi Arabia where he had spent time as a child. 

http://www.oyez.org/cases/2000-2009/2003/2003_03_6696/