Trump impeachment trial Credit: Courtesy of Senate Television via AP

The case for including more witnesses and documents in the ongoing Senate impeachment trial has been strong from the start. That case became even stronger Sunday evening, with news about former National Security Advisor John Bolton, one of several people who can and should provide additional insight in this trial.

According to a report from the New York Times, Bolton claims in a draft of his upcoming book that President Donald Trump said he wanted to tie military aid for Ukraine to political investigations by that country. If true — and that’s a big if — this would contradict Trump’s defense team.

Trump forcefully denied the assertion in a tweet later that night, and suggested that Bolton may be trying to get attention in order to help his book sales. That may also be true, but the best way to know is for senators to question Bolton under oath, as he already said he is willing to do.

What is undoubtedly true is that Trump was factually incorrect when he also tweeted, “The Democrat controlled House never even asked John Bolton to testify. It is up to them, not up to the Senate!”

The House did not go as far as it should to compel Bolton to testify, but it’s false to say he was not asked. He was asked to testify, he didn’t, and then the House failed to subpoena him. That is a mistake the Senate should not duplicate.

This back and forth about Bolton may be bogged down with falsehoods and misinformation, but it underscores a basic fact: there are potential witnesses and evidence, not currently in the record before the Senate, that can provide more information about Trump’s actions related to Ukraine, which are the foundation of the articles of impeachment against him.

“From the beginning, I’ve said that in fairness to both parties the decision on whether or not to call witnesses should be made after both the House managers and the President’s attorneys have had the opportunity to present their cases,” Sen. Susan Collins said in a statement on Monday. “I’ve always said that I was likely to vote to call witnesses, just as I did in the 1999 Clinton trial. The reports about John Bolton’s book strengthen the case for witnesses and have prompted a number of conversations among my colleagues.”

We hope that those conversations will lead to a realization among Republican senators that current and former top administration officials have plenty to add in this debate. Democrats should come to a similar conclusion related to potential witnesses such as Hunter Biden, whose work in Ukraine while his father Joe Biden was vice president is relevant here, and the anonymous whistleblower, whose concerns about aid being withheld from Ukraine in exchange for an investigation of the Bidens jump started this investigation.

Whether this additional testimony has the potential to implicate or exonerate the president, or be used for political purposes, shouldn’t really be the point. What should matter is getting a more precise sense of the truth before casting such a significant vote.

“I’ve been saying for more than a month that we should hear from John Bolton because he would be able to provide a first-hand account into what the President did and why he did it,” Sen. Angus King said in a statement to the BDN Monday. “At this point, I don’t see how anyone could say it’s not important to hear from Ambassador Bolton; to willfully ignore the implication that he has relevant facts undermines the idea that this is a real trial. One of the arguments put forward by the President’s defenders is that this information is all hearsay — so let’s get a first-hand source.”

There’s certainly been room for disagreement on when and how to include witnesses and evidence not already included in the House presentation. But as we near the end of opening presentations, it’s painfully apparent that several witnesses, like Bolton, can add clarity to the existing record and help senators cast a more informed vote.

“When we talk about our oath to do ‘impartial justice’, there is a lot of attention, justifiably so, on ‘impartial’ – but we also need to focus on ‘justice,’” King also said. “And in order to do real justice, we need to know all the facts.”

It seems unlikely that, even with additional witness and evidence, all of the facts will be known or agreed upon. But the Senate, and the American people, deserve the fullest picture possible before those votes take place. There is no doubt Bolton and others can add to that picture.

The BDN Editorial Board

The Bangor Daily News editorial board members are Publisher Richard J. Warren, Editorial Page Editor Susan Young, Assistant Editorial Page Editor Matt Junker and BDN President Todd Benoit. Young has worked...