As President Trump’s impeachment trial kicks off in the Senate on Tuesday, you’re going to hear a lot about Mitch McConnell, the Republican majority leader from Kentucky.

With the full support of his caucus, McConnell has a ton of control over how the process will unfold, and he’s likely to influence the course of the trial as much as anyone.

And if you don’t know anything else about McConnell, know this: He’s arguably the most ruthless political operator in American politics and has almost single-handedly broken the Senate. All of this matters because, in theory, a Senate impeachment trial is a solemn affair. After all, it’s 100 senators deciding whether the president should be removed from office — something that has not been done before.

McConnell has reportedly said in private that he wants a short trial with no witnesses called to testify, and he’s said publicly that the outcome of the trial is basically already determined. Given what we know about McConnell, this isn’t surprising.

As McConnell strides onto center stage, it’s worth pausing to reflect on his philosophy and the role he’s likely to play. So I contacted Alec MacGillis, author of The Cynic: The Political Education of Mitch McConnell. MacGillis knows McConnell as well as anyone, and I asked him to explain McConnell’s approach to politics and his broader impact on the Senate and potentially on the upcoming impeachment trial.

A lightly edited transcript of our conversation follows.

Sean Illing

What do you think is the most important thing people should know about McConnell?

Alec MacGillis

That he really exemplifies more than anyone else in Washington the permanent campaign mindset, where everything is about winning the next election and nothing else matters. For McConnell, it’s not really about what he does while he’s in power to address problems or purse his party’s policy goals, whatever they might be. It’s really only about setting himself up to win the next race, the next election.

That’s the only game he’s playing.

Sean Illing

Has he always been that way?

Alec MacGillis?

Yes, going all the way back to when he was a teenager in high school desperate to win the student elections. He’s always seen politics as a sport to conquer. He sort of embodies this uniquely American character that delights in politics as sport. That’s not necessarily a bad thing — it’s an American tradition in a weird way.

But if the desperation to win carries you in the wrong direction, if it overwhelms everything else, as it has with McConnell, then it becomes something else.

Sean Illing

Does McConnell have an ideological core?

Alec MacGillis

I found it really hard to discern any ideological core as I was doing the book. It was remarkable to discover just how superficially moderate and even liberal a Republican he was when he was starting out in the ’60s and ’70s. Mitch was outspoken for civil rights when he first ran for office in Louisville for the county executive job there. He was pro-union, pro-environment, and pro-abortion rights. But then that all started to shift very suddenly once he got in the Senate.

In 1984, he won his first race for the US Senate, but barely won it. He won by only 5,000 votes in the year that Ronald Reagan won in Kentucky by almost 300,000 votes. He sort of rode the coattails of Reagan. And the lesson he took from that was that he was going to have to win reelection in years to come and climb in this new Republican Party. He was going to have to shift sharply to the right to catch up with where the Republican Party was heading.

Sean Illing

How would you characterize McConnell’s broader impact on the Senate?

Alec MacGillis

Oh, it’s been enormous. He’s undermined the institution in so many ways. There was this idea of the Senate as having a higher purpose and more collegiality than the House, and he’s just completely blown that up. He had help, of course, but he’s played such an essential role.

And what’s remarkable about it is that he has managed to do that, to undermine the institution, while at the same time continuing to be upheld as a great institutionalist by many pundits in Washington simply because he has a grasp on the fine points and all the rules of the Senate.

Sure, he understands the institution very well, there’s no debate about that. But he’s done grave damage to it with a degree of partisanship and obstructionism that is genuinely rare.

Sean Illing

What do you think his first priority will be in the upcoming Senate impeachment trial?

Alec MacGillis

It’s pretty clear that his goal is to shut it down and get it over with as fast as possible, even if that means completely breaking from the way that we’ve done trials in the past. He’s been totally brazen about his collaboration with the defendant, with the White House. And my guess is that he’ll once again be hailed as a great tactician for having pulled this off.

But calling him a brilliant strategist, or pretending that he’s more clever than his counterparts on the other side, overlooks the fact that it’s easy to win if you’re willing to blow up the rules, if you don’t care about the institution you serve.

There was nothing “brilliant” about his decision to block President Obama’s Supreme Court nominee Merrick Garland. He just didn’t care about the rules or the norms that govern the Senate.

Sean Illing

Is there anything Democrats could appeal to get to him to break his allegiance, or is it just partisan warfare all the way down?

Alec MacGillis

The only thing that would lead Mitch McConnell to hold a serious impeachment trial would be the belief that it was better for him and his party to do so. If he thought it was better for the GOP to have [Vice President] Pence replace Trump, he’d do it. If he made that calculation, he’d have no compunction about holding a legitimate trial. I honestly don’t think there’s any other reason he’d do it.

Sean Illing

So he’s a nihilist with respect to everything except winning?

Alec MacGillis

That’s a perfect way to put it.

Sean Illing

Are you surprised at all by how McConnell has navigated the Trump presidency so far?

Alec MacGillis

I’ve thought a lot about how he brought us Trump and all the different ways that he’s contributed to the climate that made Trump’s election possible. But in terms of how he’s managed Trump’s presidency, I would’ve expected to see him try harder to preserve his party in the post-Trump world and maybe maintain enough distance from Trump to reduce the reckoning that seems likely to follow when Trump’s gone. But he’s made a very different calculation.

Sean Illing

Do you have any sense of how McConnell actually feels about Trump? Is there a genuine relationship there or is it a purely transactional relationship?

Alec MacGillis

There have been a few moments in the last few years where you’ve seen glimmers of discomfort from McConnell — but nothing that even rose to the level of Paul Ryan’s criticisms of Trump. There were at least flashes of real disapproval from Ryan. But that’s partly because Ryan, far more than McConnell, actually does believe in things, apart from winning. I’m just not sure that’s true of McConnell.

Sean Illing

Can you imagine McConnell, under any circumstances, taking a stand against Trump if there was even the slightest risk of party disunity?

Alec MacGillis

Well, we haven’t seen it yet. And there have been so many opportunities to take a principled stand. It’s just hard to imagine McConnell ever rising to the moment in that way. I just don’t see it.