Former Democratic senator Russ Feingold said Chief Justice John Roberts's decision on a potential tied vote on calling additional witnesses will make today one of the best or worst days in U.S. history.
"I think I can say without exaggeration this is going to be one of the best or one of the worst days in the history of the United States Senate, and this country, and specifically the United States Supreme Court," Feingold said on MSNBC Friday.
"I assume that would be quickly followed by the acquittal of President Trump," Feingold added. "We've always had witnesses in these trials, and the fact is this may be a tie ... and if it is a tie, the chief justice has every ability to vote to break that tie."
Feingold said that in the case of a tie, Roberts ought to vote in favor of calling additional witnesses.
"The chief justice has to decide not only what he should be doing in terms of this trial, but in terms of the role of chief justice as the protector of the rule of law," Feingold said.
He said he voted to confirm Roberts in 2005 believing that he abides by the law, and not casting a tie-breaking vote to allow witnesses would contradict Roberts's commitment to justice.
"If the chief justice shirks his responsibility here," Feingold said, "it is an historic moment and it is very damaging to the Supreme Court as well as to the Senate if this becomes the kind of fraudulent outcome that I'm afraid it might have."
Feingold was the only Democratic senator to vote against the motion to dismiss the case against former president Bill Clinton during Clinton's impeachment trial.
Sen. Lamar Alexander (R., Tenn.), a potential swing vote on the question of witnesses, said he opposes calling additional witnesses, setting up the possibility of a tie.