Let's see, he's 19 now - that means he became "disenchanted" at 15, and had already met terrorist trainers at his Islamic Center and was trying to blow up a building last year, at 18?
I'm not sure the issue is immigration. The issue is Islam. We have an "Islamic Center" here in Gainesville that has just put up a new sign and appears to have expanded its activities, which are directed primarily at Muslim students at the University here. It is run by the "Islamic Council" here, part of the network set up by the U Tampa prof whom the US is now trying to deport for terrorist activities.
I never thought I'd find myself saying this, but I must admit that I hope it's being watched very carefully. No more teenage (or any other) terrorists!