Over 400 people convicted of terrorism in the US have been released since 9/11, with with little if any monitoring by law enforcement.
"[This] might suggest U.S. government officials believe they can be fully rehabilitated following minor prison terms. A more likely explanation is that many of these so-called terrorists weren’t particularly dangerous in the first place."
A group of Miami men who discussed a bomb plot with an undercover informant "spent six to 13 years behind bars; they couldn’t become cooperating witnesses, because they didn’t know any real terrorists. But the more dangerous a defendant, or the more extensive his contacts with terrorists, the more likely he can leverage his connections for leniency."