This is going to be embarasing the next time there is a major terror attack (hopefully it won't happen, but statistically it is likely eventually) when it turns out that they had the data on everybody but somehow didn't act on it.
It's far easier, after you know what happened, to go back to the data and "connect the dots" to claim it should have been foreseen and acted upon. But beforehand, the dots could have been connected in any number of permutations and paths, so it becomes impossible to act on every possibility that can be forecast in advance.
