Police and intelligence agencies have an enormously difficult job because radicalization pathways to violence are not always straightforward. Sometimes an individual on the periphery of an investigation, who is assessed as low risk, rapidly becomes a threat. Similarly, an individual considered very dangerous may never act or may disengage from extremism. As the 2009 investigation of al Qaeda operative and New Yorker Najibullah Zazi demonstrated, the manpower needed for physical surveillance of even a single individual requires dozens of agents and hundreds of man-hours, and that doesn’t include the analytic team required to evaluate electronic communications such as email, chat, tweets and phone data.
In the past, Western intelligence organizations intercepted communications that allowed security agencies to move against al Qaeda or ISIS operatives, often before they could strike. Now end-to-end encrypted communications apps like “Telegram” have become standard operating procedure among terrorists. So intercepting and deciphering communications is far more difficult, even for organizations as sophisticated as the National Security Agency or the FBI.
There is no doubt that al Qaeda and its remnants as well as Islamic State have the intention and capability to strike the United States using Western operatives. What happened in Paris can happen here. A false sense of security will be deadly. The U.S. must mobilize at home and lead abroad to defeat this increasing threat.