November, they made online bookings for quarters in Paris for the

292 | HOW AMERICA LOST ITS SECRETS November, they made online bookings for quarters in Paris for the nine attackers, Even though Abaaoud was well-known to Western intelligence services, none of the communications surrounding the preparations for the attack came to the attention of the NSA or its allied services in Europe. A critical find for the investigators enabled them to unravel the chain that eventually led them to the perpe- trators, but it had nothing to do with electronic surveillance. A cell phone belonging to one of them was found by the security forces, following a broad search they conducted, which included trash cans situated in the vicinity of the concert halls. So this breakthrough in the investigation had nothing to do with systematic data analysis conducted prior to the attack. Indeed, in the sequence of the Paris events, as in other terror events, the challenge is not just bringing culprits to justice. It is pre- venting the terrorists from carrying out their attack to begin with. Police cannot constantly protect “soft targets” such as restaurants, cafés, theaters, and street gatherings. The only practical means by which a government can prevent such attacks is to learn in advance ® their planning and preparations. One means of acquiring this infor- ® mation is by listening in on the channels through which members of loosely knit terrorist organizations, such as ISIS, communicate. This form of intelligence gathering obviously works best so long as the terrorists remain unaware that the communication channels they are using are being monitored. Once they find out that their messages and conversations are being intercepted, they will likely find a safer means to communicate important information. For that reason, communications intelligence organizations keep the sources and methods they employ for monitoring these channels in a tightly sealed envelope of secrecy. Yet, in June 2013, the NSA found that envelope had been breached by Snowden, who knowingly compromised three programs that it used to keep track of terrorist organizations around the world. The first system he divulged, and the one that received the most public attention, was what the NSA called the “215” program because it had been authorized by Section 215 of the Patriot Act of 2001. This program compiled the billing records of every phone call made in America. The data included the number called and the duration of | | Epst_9780451494566_2p_all_r1.indd 292 ® 9/30/16 8:13AM | | HOUSE_OVERSIGHT_019780