who don't mind the intrusion on their privacy aren't also demanding some greater transparency, so they can be sure that the power to listen in on their phone calls isn't being abused... ?
The key piece of history to remember (lest it repeat itself) would be J. Edgar Hoover's FBI, which was granted surveillance powers in the 1920's in order to support Prohibition. By the Nixon adminitration's time, tts powers gradually expanded and morphed into a deadly political tool, with people placed under surveillance for purely political reasons. I think most people would agree that this was wrong.
So why would we want warrantless wire-tapping, or unsupervised call-listening? Even after-the-fact warrants would at least constitute a record of whose call was listened to, and by whom. Without that, it's perfectly conceivable that Karl Rove could listen in on all the Democratic National Committee members' calls in preparation for the next election. And don't tell me that some kind of ethics is going to stop someone like him from behaving just as badly as Nixon did! There's not one reason to believe that every person involved with the NSA programs is so reliable (think of all the spying scandals among people with security clearances, for example).
Mariner.