A coalition of academics and librarians have taken a "friend of the court" approach to the FCC when it comes to the ever advancing desires of the FBI and other law enforcement organizations to be able to wiretap.
It should come as no surprise, as the community is largely liberal in heart and mind, providing some of the greatest thinking which empowers both creativity and free expression.
I think we will end up at the Supreme Court level when it comes to wiretapping voice at some point down the road, and like the Miranda decision that said police officers need to read suspects their rights at the time they are being arrested, some group of judges will decide how and under what situations law enforcement can tap a VOIP call. Under traditional telephony tapping laws, a court order, signed by a judge, under the face of some evidence can order a tap, or get call records "dumped" (i.e. a printed out list).
What I'm not sure of, is if under CALEA the need for the court order still applies. That's where the highest court in the land will have to come into play.