Seems to me that many of the problems organizations like the FBI think they face stem more from the change from law enforcement to crime prevention. Crime prevention requires massive amounts of data to be collected and ultimately freedoms curtailed for specific individuals who evince a pattern of behavior demonstrated to lead to crime. With organizations like the FBI, NSA, CIA, etc. all tasked with preventing another 9/11/2001, they understandably want the data to be able to proactively root out those individuals who might be likely to pull something like that off.
I'm not saying I agree with what guys like Brennan are asking for, but I am saying that they realize their responsibilities have changed and they are demanding the tools to do so. From their perspective, they probably don't understand how the people can say over and over "you'd better not ever let anything like that happen again but you can't infringe on any of my rights in order to make that happen". To a professional law enforcement officer, even a bureaucrat, that is a contradictory statement. Worsening matters is the ham handed way in which they've chosen to implement everything and how the American people have come to know how these things are being done.
You can't have the kind of safety people seem to expect today without a significant infringement of your rights.
Of course you can't flap your arms and fly to the moon. After a while you'd run out of air to push against.
