The people who are here in this country, who are "suspected" con-sonspirators or sympethizers are here because the government let them in via work or student visas. Most of them, that is. Most will never talk, and there obviously is not enough evidence to link most of them to a crime. So, they must be deported. If they "get back in", then it should be because they sneaked in.
Some people say, "But FT, these people are more than likely terrorists; we can't give them another chance to act!" Well, what we have then is one of these "I know, but I can't prove it" hunches. It may be valid. We have two choices in that case. 1) We disregard the rule of law, and imprison or execute anyone the government "claims" is a terrorists, supporter or sympethizer. Or 2) We deport them, and don't let foreign nationals and radicals in our country.
I'll go with number two.