No Fifth Amendment protection. No subpoena immunity. Libel is not Constitutionally protected.
Good point. Thor mentioned that Democrats were furiously fighting discovery against Fusion GPS. He said that is becasue discovery will reveal just how deep the Democrat party and it's organs are involved with the company. For example Thor claimed Fusion GPS paid reporters to run stories. He also mention it was dictorial regimes who were giving the company lots of money to do the dirty work they do.