"Why? What good are they to us alive?
Try them and execute them."
While I agree with you, I don't see it happening, the US government is losing the PR war on this one.
In the long run, the PR is worse if we keep them alive. If we execute them, the left will have a hissy fit for a few months, and then it will blow over.
If we keep them alive, they're a prepetual pretext for America bashing.