Pat A. Cipollone, White House Counsel, participated in the events leading up to the impeachment of Donald J. Trump. That makes him a witness, whom the House managers might want to call to testify. But Cipollone is also heading the Trump defense. A legal ethics rule – the “advocate-witness rule” — says that when a lawyer should be a witness at trial, she cannot also be an advocate in the courtroom. The Senate chamber is not, of course, an ordinary courtroom, but that should make no difference. The goal is the same – to get the facts and find the truth.

Citing the advocate-witness rule and abundant legal authority, the House managers wrote to Cipollone on January 21 demanding that “at a minimum, you must disclose all facts and information as to which you have first-hand knowledge that will be at issue in connection with evidence you present or arguments you make in your role as the President’s legal advocate so that the Senate and Chief Justice can be apprised of any potential ethical issues, conflicts, or biases.” The House managers are right.

The advocate-witness rule tells us that it is more important for a lawyer with first-hand information about the events on trial to testify than to work as an advocate. That will mean that a client will not be able to get the lawyer he wants to represent him in court. But when the client’s interests and the court’s interest clash in this way, the rule says quite clearly that the court wins.

It doesn’t matter whether the lawyer’s testimony would help the client or the client’s opponent. In either event, the court’s interest in the testimony will prevail over the client’s wish to hire the lawyer. And especially if the testimony could help the opponent, the rule prevents the client from blocking it through the expedient of hiring the lawyer. The rule has exceptions but none applies here.

From all that appears, Cipollone is what the law calls a percipient witness to the relevant facts. He has personal and significant experience with the events that form the basis for the articles of impeachment. His testimony would not be hearsay. If the impeachment trial were in a courtroom, Cipollone could not head, or even be part of, the defense team. The same should be true in the Senate trial because, at bottom, the senators have taken an oath to perform the same job that we ask of traditional jurors – i.e., decide the facts. To do that job, they need to hear from the witnesses to those facts.

“In a courtroom, by contrast, jurors would not be allowed to deliver a verdict without hearing witnesses. … Here, however, the Chief Justice, who is presiding, appears unwilling to rule that the trial should include witnesses.”

There is, however, one difference between the Senate trial and a courtroom trial. The senators may choose to issue their verdict without hearing witnesses. They have the power to do so. In a courtroom, by contrast, jurors would not be allowed to deliver a verdict without hearing witnesses. In court, the litigants would have the right to call witnesses and the judge would protect that right. Here, however, the Chief Justice, who is presiding, appears unwilling to rule that the trial should include witnesses. Consequently, the senators are the judges and the jurors. If they forego witnesses, does the advocate-witness rule become irrelevant?

No. Because Cipollone participated in the underlying events, facts he implies in his advocacy can appear particularly credible. After all, he was there. Yet he will not have been placed under oath and he will escape cross-examination, traditional safeguards for ensuring that testimony is truthful. In this way, he gets advantages that hinder his opponents. He is both a witness and not a witness simultaneously.

With no real witnesses, the Senate will be moving into Alice in Wonderland territory. Following the trial of the Knave of Hearts, the Queen of Hearts pronounced “sentence first, verdict after.” In the Senate, with no witnesses, this sequence will change. It will be “verdict first, trial never.”

Photo: In this screengrab taken from a Senate Television webcast, White House counsel Pat Cipollone speaks during impeachment proceedings against U.S. President Donald Trump in the Senate on January 25, 2020 (photo by Senate Television via Getty Images)