I think targeted surveillance is not enough - if you find a suspect, I think you need to take the bulk surveillance data and look at what that person communicated in the past and whether he is indeed a suspect, not just watch him only from this point on.
Considering the bulk approach is what they've been doing for 10 years or more and terrorist attacks continue to happen, usually by people the intelligence agencies already identify as risks, it doesn't seem to be at all effective.
The bulk approach leads to a saturation of data. That doesn't make things easier, it complicates them.
