This is rubbish. There is a litany of recent, memorable cases. But they rarely met the legal threshold of contempt of Congress, and in the cases that did, there was seldom political will to prioritise its prosecution.

Congress, by design, is a political creature. We don't want the President (DoJ) rounding up people who speak to a co-equal branch of government because he--unilaterally--thinks they might have lied.