OK. I don't know if you're a lawyer, but your username is suggestive. The US Supreme Court has ruled three times on this, most recently in 2008. The detainees have a right to counsel and cannot be held indefinitely without charges.
http://www.msnbc.msn.com/id/25117953/
So what do we do? I thought that by classifying some detainees as POWs we could be hold them until the "end of hostilities"; a point in time which we define. (see my previous post #48). The US needs to find a way to charge the worst of them or I'm afraid the courts will order them released.
As for formal declarations of war, I discuss this in post 23. Since the adoption of the UN Charter in 1946, countries don't declare war on each other any more.
http://pediaview.com/openpedia/Declaration_of_war