Mueller is the only person in the entire country that can do this.

Make it politically difficult for the Republicans in the Senate to vote against impeachment. Mueller is the only one who can appear in public, under oath and tell the American people that Trump and Barr are not telling the truth about his report.

He is the only one who can tell the people what he really meant about the evidence in his report and what he expected to be done about it. He is the only one most Americans will believe. It's his report, his investigation.

Mueller is the whole dam ball game. He has been from the very beginning.