Why wouldn Congress give McNamee immunity?
Immunity is rarely granted. The last time the Committee on Oversight and Government Reform gave a witness immunity was in 2003, when testimony involved an ongoing criminal investigation. One reason that Congress might deny McNamee immunity is if the Justice Department has made it clear that it is still investigating McNamee. If McNamee were given an immunity deal the Justice Department could still prosecute him if it obtained information about his crimes independent of his testimony. As a general rule, though, it is very hard for a prosecutor to prove that information was not gleaned from immune statements if the testimony was given publicly, and the evidence is liable to be thrown out.
