It was in early fall, before the House formally announced an impeachment inquiry, when Sen. Doug Jones (D-Ala.) told his staff: “Gear up.”

At the time, Jones wasn’t sure whether the Senate would even take action on impeachment. But, the former prosecutor said, the evidence was compelling enough for him to want to become an expert on impeachment, legally and historically. He asked his staff to start meeting on the topic, and collect all the research they could for him to read.

The intensive prep work might also have something to do with the fact that a lot of eyes will be on him throughout the Senate’s proceedings. Jones is in an unenviable position, politically speaking. First, he is a Democrat from a solid red state that has shown considerable support for President Trump — more than 62 percent of Alabama voters backed Trump in the 2016 presidential election. On top of that, the 2020 race for Jones’s Senate seat has been deemed the only true toss-up one among all races for Senate seats held by Democrats in this cycle. Former attorney general Jeff Sessions, who used to hold Jones’s seat, is among the Republicans vying for the nomination to face Jones.

On impeachment though, Jones has stuck with his party. He has said, for example, that he would vote to call witnesses such as former national security adviser John Bolton in the Senate trial.

The Washington Post sat down with Jones to discuss his perspective on the Senate’s impeachment trial and how he’s navigating it as a tough race looms. The interview has been edited for clarity.

How are you specifically preparing for this Senate trial?

Jones: I started kind of early on because I am a trial lawyer. For 40 years, that was what I did. And I’ve prosecuted big cases. I’ve defended big cases, and been involved in whistleblower cases. And so when this thing first hit, when the complaint just became acknowledged that there was a complaint, it caught my eye because the allegations were such that I thought they were very serious.

As it got more intense in the House of Representatives, we had more stuff to read. And every so often, we would get the transcripts, once transcripts of testimony were made public. We would immediately get them. We put them on our server. I’m still kind of old school, I like to have a lot of printed stuff. I would take it. I would try to read it as much as I can at night. During the times I’d read it on airplanes, I tried to disguise what I was reading (laughs).

We started looking at the rules of evidence. We started looking at various statutes that might be implicated, criminal statutes, doing things outside the four corners of just the investigative process to get a feel. And, of course, looking at history, reading some of the Federalist Papers or at least going through summaries of those about what the impeachment is. I wanted to be sure that I did as much work as possible to understand where we’re going and what we’re doing.

With all of the background knowledge that you now have on impeachment trials, do you think that the Senate is going to follow the right protocols for these proceedings?

Jones: I don’t know the answer to that. I know that it looks like initially we’re going to do it in a way that I don’t think is the right way. You know, there’s been a lot of talk about comparing this to the [President Bill] Clinton trial, and you can learn a lot from reading that transcript. But in that investigation, there was an independent counsel investigation. The House did want every witness in that case who had been interviewed multiple times or gave testimony multiple times. We don’t have that here. We’ve literally had the president, the administration blocking key witnesses. They wanted to block even more. They’ve not turned over documents. Documents are used to test the credibility of so many of the witnesses. They got to review documents. But we’ve not been able to look at them to test that credibility. I think that that’s really needed here.

But for me, it’s very important that we have a full, fair and complete trial. And so I’ve been pushing for that. Trying to do that in a nonpartisan way, because I really listened when the president said he wasn’t getting a fair shake in the House. I’m not sure I agree with him completely because he opted not to get involved in a lot of things. But be that as it may, I wanted to make sure that when it came over to the Senate, that not only the president was getting a fair shake, but the American people are getting a fair shake. And I don’t think they will if we don’t hear from at least a few of these witnesses.

Given Alabama’s support for President Trump, do you find that your beliefs on impeachment and how the trial should go are hard to convey to your constituents?

Jones: No, I don’t think so at all. Look, the people that voted for Donald Trump are the ones that deserve to know the truth the most, not the people that opposed it. One of the problems that we’ve had in this impeachment inquiry is that so many Democrats called for his impeachment the minute he took his hand off the Bible when he was sworn in. But the people that voted for him, and that are still supporting him, they are the ones that deserve to know the truth one way or another.

They deserve to know if President Trump abused his office or not. And those facts are what I’m looking for. Those are the facts. Now I’ll look and make a judgment on whatever’s in front of me. But at the end of the day, I think people deserve to have the full truth and the complete truth as much as possible, and not to get stonewalled … by … [Majority Leader] Sen. [Mitch] McConnell or the administration.

Does the fact that you’re in a toss-up reelection play into any of your preparation?

Jones: It never has. I think that you’ll find from my staff that tough reelects are not discussed around here. A lot of votes we take are easy votes, either for or against something. But the tough votes, I want to be able to go back to Alabama and be able to explain why I voted in a way that is not in a political way, because people see through that.

If the Senate only gets one witness, who is the witness that you think that should be?

Jones: Well, if we only got one witness, I would probably go with [acting White House chief of staff and Office of Management and Budget Director Mick] Mulvaney, because I think the Office of Management and Budget, their fingerprints are everywhere in this. It was from OMB that the directive was made to withhold the foreign assistance. And the OMB director happens to also be the acting chief of staff. So if I could get one witness and the documents that are there to either support the testimony or to test that testimony, it would probably be Mulvaney. I think John Bolton is a pretty close second, but Mulvaney would be my first choice. But I dare say that that is probably not going to happen.

I’m looking at it as a lawyer and what my training is and trying to piece this together. And, you know, there are times that if we do get witnesses, they’re probably just going to have to strap me in my chair, that I don’t get up and want to ask a question, because that’s just my nature. I mean, you know, I want to be part of that — to ask the question and not just write it down and hand it to somebody — but we’ll see how it goes.