This is a fascinating debate between Ron Paul and William F Buckley on the necessity of the FBI and CIA. The debate has 3 more segments, but this is the segment which pertains to the topic.
Buckley makes the argument that without Federal agencies, kidnap victims would be vulnerable to negligence due to abductors who cross state lines. Ergo, a coordinated effort wouldn't be foreseeable since state agencies wouldn't know where to go, nor would they have the instantaneous authority to give pursuit.
On the other hand, Paul argues that without secret agents in the first place, society wouldn't have the motive to commit heinous acts since society would openly communicate, so people wouldn't find themselves in awkward situations.
Similarly, Ron Paul emphasizes J Edgar Hoover's usage of covert intelligence as a political weapon despite Buckley's claim that intelligence agencies are held to far stricter rules. It isn't just domestic policy he complains about either, but also the matters of Beirut and Iran-Contra where covert intelligence is just so bad.
What I find ironic about the debate is Ron Paul comes off with a warmer, more sociable attitude than Buckley despite being the libertarian. You would expect Buckley to be the warm one because conservatism embraces social values, but here, he gets put in the awkward position of defending the cold character of covert intelligence.
In any case, is covert intelligence valuable?