David Mortlock is the author of a recent article on this topic in the Harvard Law & Policy Review.
The United States has yet to settle on a definition of enemy combatant. The Supreme Court spent the past decade determining whether and how detainees could challenge their detention but explicitly avoided the question of whether they could be detained in the first place. The debate has divided not only political rivals, but also, as the New York Times recently detailed, seniors official in the current Administration.
A handful of district and circuit courts have begun to examine the scope of the President's authority to subject enemy combatants to military detention without charges, a jury trial, or any of the other trappings of criminal detention. Some parties have taken the position that the President lacks detention authority in the fight against a terrorist group, while others argue that the President may detain even unwitting supporters of al Qaeda. The courts have reached a number of different conclusions.
In my article, Definite Detention: The Scope of the President's Authority to Detain Enemy Combatants, I suggest that Congress has authorized the President to subject members of al Qaeda and the Taliban to military detention, whether or not they engage in combat. However, the President may not use military detention for mere supporters or sympathizers of those groups. This membership model could also be used to determine the appropriate time for release. Namely, detainees could be freed when they sever their membership in al Qaeda or the Taliban.
Nonetheless, the debate is far from over. While a number of district courts have adopted this membership model, the D.C. Circuit recently suggested in dicta that an individual could be subjected to military detention merely for supporting the Taliban. The decision indicates that this debate could continue for many years.
In my essay, The Limits of Advocacy: Lawyers for Terrorists/Lawyers for Torturers, I discuss why the role of the defense attorney and the multi-faceted role of the government lawyer are not equivalent. I also discuss the reasons why we have developed clarity about the role of defense attorneys since the dark days following 9/11: the military lawyers who led the way, the organized bar gradually stepping up to the task of defending the Guantánamo detainees, and the Supreme Court deciding a series of cases making a strong statement about the essentiality of the rule of law and lawyers, even at Guantánamo. 
"Proposals like Sen. Joe Lieberman's to take away a suspect's citizenship put the nation on a dangerous path," 
The Supreme Court on Monday 
The U.S. Supreme Court passed on a chance to hear the