What would it take for Baker to win a third term over the competition?

Gov. Charlie Baker has been saying for months that he'd announce whether he'll run for a third term sometime this fall. But with the holiday season approaching, Baker is cutting it close if he wants to keep to that deadline. GBH News State House reporter Mike Deehan joined host Sean Corcoran on Morning Edition today to discuss Baker’s choice. This transcript has been edited for clarity and length.

Sean Corcoran: Mike, Baker was on GBH's Boston Public Radio yesterday and he was asked again, as he gets asked in almost every interview he does these days, if he's decided to run again and nothing new there.

Mike Deehan: Yeah, poor guy keeps getting asked if he's going to be governor all the time. He adamantly said "soon," as he has over and over again. The governor keeps saying that he and Lieutenant Governor Polito will decide pretty soon whether or not to run.

But of course, there are plenty of complications over how he would run and if he would want to run as a Republican this time around versus an independent, which is a rumor that's really gained steam lately, or at least a path that people are saying would be better for a moderate like Baker. Especially because the Republican Party has really shifted in the seven years that Baker's been governor, away from his moderate Bill Weld-style Republicanism towards much more of a Donald Trump-oriented conservative Republicanism. And Baker just kind of finds himself a man without a party to a certain extent. And that could mean a very, very strong challenge in the 2020 Republican primary from former Whitman representative Geoff Diehl, who's running as a far more Trump-friendly Republican already in this race.

Corcoran: All we've heard for years is he's the most popular Republican governor in the country, so it's really hard to kind of get your mind around how he could do so poorly in his own party's primary.

Deehan: Yeah, and there are a couple of polls now that suggest that a) he would have a very hard time beating Diehl in a Republican primary and that b) he would have a pretty good time running as an independent.

That's because the Republican Party, you have to remember, in Massachusetts, it represents less than 10 percent of all voters in the state. It really is a small party. It's a major national party, but it's small here in Massachusetts. They don't have that many voters, but the ones they do are pretty conservative and they're very worked up and they're very motivated by Donald Trump and by a candidacy like Geoff Diehl.

They have kind of had a messy divorce from Baker over the last few years in their internal politics. So it's really stacking up where this popular Republican governor in a Democratic state might have to back away from his party, the party he's been in for his whole adult life in order to keep his seat for a third term.

Corcoran: Is he setting himself up basically for failure if he runs in the Republican primary?

Deehan: So on Boston Public Radio yesterday, he was asked by Jim Braude, “is it safe to assume that if you run, you will run as a Republican?” And Baker said, “yes, that is a safe assumption to make.” It wasn't an ironclad “yes, I will run as a Republican,” but it looks like that's what he's going to do. Now, the way around this, while still staying Republican and getting a Republican primary is to attract moderate voters from the middle because the Democratic Party in Massachusetts is only about a third of all voters. That means the rest of them — that fifty five percent are independent unenrolled voters. If they like Baker, that's where his popularity comes from.

If Baker can attract those unenrolled [voters] to work within the Republican primary next year, he can really swamp, with moderate voters, the conservative party members, who will be kind of outgunned. And Baker could pull that off. A lot of different things have to happen. It means the Democratic primary has to be uninteresting. And it's really too early to say whether or not we're going to have an uninteresting Democratic primary race.

Corcoran: One person who possibly would be involved in that Democratic primary would be Attorney General Maura Healey. I feel like we've been waiting for her to tell us whether she plans to run for governor as well. Do you think she's waiting to see what the governor does?

Deehan: Yeah, it all comes back to that game of chicken that Baker and Healey have apparently been playing with each other — whether or not, who runs and what it means, because Healey might not want to run against a third term Baker and Baker might not want to have to put up a fight against Healey because she'd be a contender for the Democratic primary, and maybe be able to beat him in that general election. The other Democrats in the race, Baker would have an easier time with.

So if Healey is in and she's attracting a lot of attention to the Democratic side of that primary, that means fewer moderate middle-of-the-road unenrolled voters for Baker to have on his side. So it's kind of this proxy battle on primary day that we don't usually have around here.

Corcoran: GBH Statehouse reporter Mike Deehan always at his best, trying to predict the future. Thank you, Mike.