Terrific op-ed piece in the Wall Street Journal by UC Berkeley law professor John Yoo (link is for subscribers only):

Taken as a whole, the Court’s message is unmistakable: The days when terrorism was merely considered a law enforcement problem and our only forces were limited to the FBI, federal prosecutors and the criminal justice system will not be returning.

Following judicial precedent and common sense, a plurality of four justices in Hamdi agreed that waging war must include the power to detain enemy combatants. Justice O’Connor’s opinion made clear that detention in wartime is not a punishment, and so does not deserve the trappings and procedures of the domestic criminal-justice system. As she observed, “the purpose of detention is to prevent captured individuals from returning to the field of battle and taking up arms once again.” Enemy combatants can even include American citizens who join al Qaeda or the Taliban. Brushing aside the argument that Yaser Hamdi’s detention was illegal because it was indefinite, the Court affirmed that an enemy combatant may be detained for as long as active hostilities continue, as they do in Afghanistan.

Upholding the detention of citizens who join the enemy is perhaps the most significant aspect of this week’s opinions…

UPDATE: William Sjostrom informs me that Yoo’s article can be viewed for free here.