According to this NY Times story, the homeland security types don't like the stupid network. The FCC is right to favor the stupid network, but I could see them being forced to buckle.

Law enforcement officials have also warned the F.C.C. that the approach that Mr. Powell has begun to articulate to have few regulations over the emerging technology that will permit consumers to use the Internet to send and receive phone calls could make it significantly more difficult for prosecutors and federal agents to monitor those calls.

My message to the FBI (not that anyone would listen to me) is that there are plenty of technological advances that make their job easier. Maybe it will be harder to tap phone conversations in the future, but get over it. The biggest problem for law enforcement is not voice over IP. It's internal bureaucratic stupidity.