And in the early days of the war against al Qaeda, the enemy was still using means of communication that American intelligence had the ability to monitor — including satellite phones and such — leading to several counterterror coups and high-level captures. But the network learned quickly and adjusted, becoming far more elusive, more dispersed, its cells increasingly attuned to operating independently, its nodes and links ever less visible. It was against this shift that something like PRISM had to be mobilized to improve our ability to find the foe whose best, and only real defense against us is his capacity for concealment.

Thus, the tantalizing prospect of PRISM, and of the whole “finding effort,” is to deny the terrorists the virtual haven that they enjoy throughout the world’s telecommunications spaces — indeed, throughout the whole of the “infosphere,” which includes cyberspace. The piercing of this veil would mark a true turning point in the war on terror, for al Qaeda and other networks simply cannot function with any kind of cohesion, or at any sort of reasonable operational tempo if their communications become insecure. Cells and nodes would be ripped up, operatives killed or captured, and each loss would no doubt yield information that imperiled the network further. Even if al Qaeda resorted to the drastic measure of moving messages, training, and financial information by courier, operations would be so slowed as to cripple the organization. And even couriers can be flagged on “no fly” lists or caught boarding tramp steamers and such.