Charlie Baker, the most popular governor in America, looks like a lock for reelection, according to polls, pundits, and even lots of Democrats you talk to. But don’t count John Walsh as one of them.

The former chairman of the Massachusetts Democratic Party insists Baker can be defeated — and he says the governor’s team knows it. It explains why, Walsh says, Baker is furiously raising millions of dollars for his campaign — and bending all sorts of campaign finance rules to do so.

Is Walsh onto something, or is he on something?

MassINC Polling Group president Steve Koczela and I poke at this question with Walsh in this week’s Codcast, in which the well-respected Democratic strategist unspools his against-the-grain thinking. Walsh also lays out his arguments in this piece, which went out yesterday to CommonWealth email subscribers as the weekly Upload commentary.

Walsh makes his case in three parts, based on what he says are “values,” the numbers, and organizing.

On values, he says Baker has tried to present himself as “not really a Republican.” That has alienated the conservative base of the Republican Party, which Baker needs to win, says Walsh. That explains some of his nods to the right to mollify that group, including appointing the president of the local affiliate of the NRA to a state post, moves that Walsh says should give pause to progressive-leaning voters.

On the numbers, Walsh says a long string of elections, both for president and governor, show a ceiling of about 1.1 million votes on what a Republican can capture in Massachusetts. If Democrats can boost turnout this fall beyond the usual 2 million to 2.2 million voters that show up for gubernatorial elections, he says that will spell trouble for Baker and be good news for the Democratic nominee.

In his piece for CommonWealth, Walsh goes through an impressive list of elections in which the Republican candidate for governor or president in Massachusetts won 1.1 million votes. But he leaves off the one race that some think may be the model for what’s unfolding this year: The 1994 election in which Baker mentor Bill Weld rolled to a landslide reelection win with 1.5 million votes.

Walsh also argues that there will be lots of grassroots organizing that can boost the Democratic nominee’s chances — whether it’s from the campaigns of Elizabeth Warren and Maura Healey or several questions heading for the November ballot.

Even if you buy Walsh’s argument that Baker’s prodigious fundraising is, in an upside-down way, a sign of weakness, it’s hard to see the anemic fundraising numbers posted by the two Democrats vying for the nomination, Jay Gonzalez and Bob Massie, as a sign of strength. Add to that their low name recognition five months from the election and the two candidates’ standing is a far cry from that of first-time candidate Deval Patrick at this point in 2006. Walsh was the campaign manager behind Patrick’s victory.

If there is any opening for Democrats, says Koczela, it may lie with the fact that Baker gets positive ratings in polls but on very few things do voters rate his performance as excellent. “People don’t love Charlie Baker, they never really have loved Charlie Baker,” he says. “But they like Charlie Baker. They think he’s doing well enough.”

Walsh points to polls showing Scott Brown approaching 60 percent favorability on the day before Elizabeth Warren knocked him out of his Senate seat in 2012. Voters “liked Scott Brown, but they voted against him based on policies and a ground game that really impacted,” says Walsh. “That’s the place that Democrats need to get to,” he says of this year’s race. “I’m not saying it’s guaranteed, but anyone who thinks it’s not possible has not been paying attention.”