When it comes to challenging President Trump in a 2020 primary, John Kasich seems to have moved from “no” to “unlikely” to “who knows what'll happen?”

During a March appearance on CNN's “State of the Union,” the Ohio governor said he wasn't interested in running for office again and repeatedly said “no” when asked whether he'd primary Trump. Two weeks ago, he talked to CNN again and said it was “very unlikely that I will run for public office” but added, “If I see something I need to do to help my country, that I really believe that I have to do, then I would think I would probably do it.”

Then he talked to Bill Maher on Friday night and sounded like a guy who may well be in the market for a new project after he's finished as governor in January 2019.

Here's the exchange, which Maher began by urging Kasich to do it for the good of the republic:

MAHER: I could see a challenge in the Republican Party for 2020. Would you be up for that?
KASICH: It — it all … [AUDIENCE APPLAUDS] No, no, no, no, no. Look, I'm going to …
MAHER: You wouldn't challenge him as a sitting president?
KASICH: That's so — it's so speculative. And look, I'm going to finish my term in 18 months as governor of our state, pull the state together and get it to do better and better and better. That's what I'm all about — and giving everybody a shot. And then I don't know what I'm going to do. I'm going to keep a voice, but I can't predict to you — I never thought I would be governor, I never thought I'd go back into politics. So, what I look for is, ‘What is it I'm supposed to do? What is it I'm supposed to do in my lifetime to build a better world or build a better community or whatever?’ And so I can't tell you what that's going to be, and I'm not plotting and scheming. I'm rooting for him to do well, Bill, for the same reason I root for a pilot on my airplane to do well. Okay? He's the president.

It's pretty clear Kasich is leaving the door cracked open here. The “no no no” part was less a “No, I won't run” and more intended to temper the crowd's enthusiasm. The rest of Kasich's comments suggest that he may very well feel called to take the plunge in 2020. At the very least, he's conspicuously leaving it open as a possibility in a way he didn't just six weeks ago.

Either that or he just realizes that keeping this possibility open is the best way to retain a platform. Without being Trump's potential primary challenger, he's just the outgoing governor of Ohio who won a state in the 2016 presidential race.

But it's also clear that Kasich sees some value in being a prominent anti-Trump voice. He has said that he didn't vote for Trump in 2016 and has been vocally critical of the president in a way even other skeptical Republicans haven't been. He's even got a book coming out on the subject. Either Kasich feels called to be the conscience of his party or that's his political angle; either one seems like motivation to potentially run in 2020.

I'd still consider it unlikely, if for no other reason than that primarying a sitting president is usually a thankless task. No president has ever lost a primary, in fact. Pat Buchanan took nearly 3 million votes against George H.W. Bush in 1992 but didn't carry a state. In 1980, Ted Kennedy took 12 states against Jimmy Carter. In 1976, Ronald Reagan came as close as anybody and narrowly lost to Gerald Ford. All three sitting presidents wound up losing the general election.

There is one case in which the threat of a primary challenge paid dividends. In 1968, Eugene McCarthy and Robert F. Kennedy both jumped into the race against President Lyndon Johnson, with Johnson later withdrawing rather than face defeat.

The major problem for Kasich right now is that there is very little sign that the Republican base is unhappy with Trump and is looking for an alternative. While the president is broadly unpopular on a historic scale early in his presidency, a recent Washington Post-ABC News poll showed 62 percent of Trump voters say he's been a better president than expected, while just 2 percent say he's been worse.

Kasich didn't have a ton of success as the Trump alternative in 2016, and it's not clear he'd do much better in 2020. But if Trump's base erodes over the next couple years, it's clear Kasich is positioning himself — rhetorically, at least — as the guy who could take him on. And for now, he's the biggest name who is doing that.