I’ve long advocated investigation, intelligence, and emergency response as the places where we can most usefully spend our counterterrorism dollars. Here’s an example where that didn’t work:
Starting in April 1991, three FBI agents posed as members of an invented racist militia group called the Veterans Aryan Movement. According to their cover story, VAM members robbed armored cars, using the proceeds to buy weapons and support racist extremism. The lead agent was a Vietnam veteran with a background in narcotics, using the alias Dave Rossi.
Code-named PATCON, for “Patriot-conspiracy,” the investigation would last more than two years, crossing state and organizational lines in search of intelligence on the so-called Patriot movement, the label applied to a wildly diverse collection of racist, ultra-libertarian, right-wing and/or pro-gun activists and extremists who, over the years, have found common cause in their suspicion and fear of the federal government.
The undercover agents met some of the most infamous names in the movement, but their work never led to a single arrest. When McVeigh walked through the middle of the investigation in 1993, he went unnoticed.
The whole article is worth reading.