The thing that always baffles* me about these government agencies wanting to broaden their powers in the name of "terrorists" or "child porn" or whatever the current boogeyman is, is the fact that all of these groups are statistically insignificant. I would guess that you could round up every single child pornographer on the planet and you wouldn't even need a single United States maximum security prison to hold them. They are not a statistical threat to our country, our way of life or, really, our children. They are aberrations. Sure, on a small scale they can cause real and very unfortunate damage, but these are not people that are going to destroy our society. Their crimes are more offensive than that of, say, a car thief but, a car thieves crimes and a child pornographers crimes are about equally as likely to destabilize our society. I can't understand why we need to treat them any differently than a common criminal*.
* It doesn't actually baffle me and I do understand why we treat them differently than a common criminal: Because those in power want to retain that power and the best way to do that is to make sure the unwashed masses don't try to overthrow their masters. A scapegoat that convinces the unwashed masses to submit to ever increasing authoritarianism is the least violent way to enslave them.