It begs the question under what terms may we detain people we are "certain" will return to the fight.  Apparently we can't, or won't prosecute them even for conspiracy to do something bad.  If we are so certain, can we not convince others in such a way to make it actually legal to keep them confined?  Instead of this back door gitmo method declared illegal by our own supreme court.  It makes us look like hypocrites.

The number returned to terrorisms (max 11% by highest estimate) is not justification for our illegal actions.  Cutting off hands of suspected thieves will certainly prevent robbery by those individuals, but we don't do it.