A young man walks into a Home Depot and buys a large quantity of acetone. Later, a young man walks into a beauty supply store and buys hydrogen peroxide. Still later, a young man is observed parked outside a nondescript federal building in a rented van, taking photographs.
No crime has been committed. But should any of these activities (acetone and hydrogen peroxide can be components for explosives) be reported to and evaluated by law enforcement officials? If they are reported, the government may infringe on privacy and civil liberties. If they are not, we might not know until it’s too late whether it was the same young man in each instance. We might miss the next Timothy McVeigh.

This dilemma was at the heart of hearings before the Senate Homeland Security Committee last week, in which several federal officials warned that “homegrown terrorists” represent the nation’s greatest emerging threat. According to the F.B.I. director, Robert Mueller, Al Qaeda “has looked to recruit Americans or Westerners who are able to remain undetected by heightened security measures.” This reality has led Janet Napolitano, the secretary of Homeland Security, to conclude that “homeland security begins with hometown security.” And hometown security begins with locally based observations of “suspicious” activity. So, can we encourage such observation without also encouraging a disregard for privacy and constitutional rights?

We may get our answer from a project now being undertaken by the Justice Department called the Nationwide Suspicious Activity Reporting Initiative. Federal, state and local law enforcement officials have set up “fusion centers” for the program in about a dozen cities, including Boston, Chicago and Houston, where reports of suspicious activities made by citizens and the local police are collected and analyzed for disturbing patterns.

Suspicious Activity Reporting begins at the troubling intersection where law enforcement meets intelligence. Its premise is that if potential attacks are to be prevented, and not merely responded to, law enforcement must focus on precursor conduct — surveillance or “casing” of bridges or train stations, for instance — that may not itself be criminal, but may signal a coming attack...
(more)