He's an American citizen. They can't (or shouldn't at least) try him or work him as an enemy combatant no matter what any senator says or what the public wants. If they do, they will basically be saying they can try any American as an enemy combatant.
I'm hearing they haven't read him miranda rights. That's not good.
Don't get me wrong, I'd love to give him the Theon Greyjoy treatment, but if they decide they can up and do that to him, they can do it to you, your family, and anybody you know based on whatever grounds they decide.
Here's a video for reference: