I've encountered this statement before. Without reading the article, here's the argumentation I heard: Basically, the perpetrators were already known - there

I've encountered this statement before. Without reading the article, here's the argumentation I heard: Basically, the perpetrators were already known - there basically was already (close to) enough information to foresee serious problems (in hindsight * ), just no one connecting the dots. Adding mass surveillance to this doesn't make things easier: signals were already swamped under, that's not going to improve just by getting more data. Rather the opposite. I don't know how this argumentation squares with the facts. But if the intelligence problem was "failure to connect dots", getting more "dots" is not a solution. * also, hindsight is 20/20.