The share of registered voters affiliated with each party has slipped, too. Democrats now make up about 24 percent of the state’s more than 5.1 million registered voters. Republicans have fallen below 8 percent, their lowest share since at least 1948. (Official data online doesn’t go back further.)
In turn, the state’s already outsized proportion of unenrolled (or independent) voters has hit a new high, accounting for just over 67 percent of the state’s total. The electorate itself is also growing. Nearly 160,000 voters have been added to the rolls since February 2025, according to the data.
That means there are even more voters who can opt to pull either a Democratic or Republican primary ballot on Tuesday. Galvin said at a Thursday news conference that he expects turnout for the primaries to be similar to, if not slightly exceed, that from the 2022 primaries.
He projected that 800,000 people would vote in the Democratic primary, headlined by the US Senate matchup between Senator Ed Markey and Representative Seth Moulton, with more than 270,000 having already cast ballots as of Thursday.
Galvin said he expected 280,000 to weigh in on the GOP primary, whose marquee matchup is the fight for the party’s gubernatorial nomination between Michael Minogue and Brian Shortsleeve. As of Thursday, 73,000 voters had already voted in that primary, which Galvin said was slightly ahead of the pace from four years ago.
With fewer registered voters in each party, however, there are also fewer dyed-in-the-wool party-goers that can participate in caucuses, help fill local political committees, or hit state conventions.
Party leaders say they aren’t pressing the panic button.
Despite the tens of thousands of voters leaving the party, state Democratic Party chair Steve Kerrigan said he’s “heartened” that when Massachusetts voters do cast ballots, they “are voting overwhelmingly for Democrats in Massachusetts.” (Democrats hold every statewide elected office, every seat in the state’s congressional delegation, and super majorities in both chambers of the state Legislature.)
Still, Kerrigan acknowledged that “partisan politics has become a pretty ugly business.”
“Average, every-day voters out there are trying to find leaders to vote for who are going to try to solve their problems,” he said.
Republicans, meanwhile, are putting their own spin on the numbers.
“Voters are tired of the extremism, dysfunction, and corruption that have defined one-party rule in Massachusetts for too long,” Haley Jones, the executive director of the state Republican Party, said in a statement. “Party registration is changing because Massachusetts is changing. Voters are looking for something different.”
The rise of the independent voter in Massachusetts isn’t new. The share of voters without a party affiliation has been climbing for years, something that’s been borne out on the ballot. Many of the Republicans running for statewide office, for example, had left the party and only re-enrolled with the GOP shortly before they launched their campaigns.
But the latest exodus comes amid a broader wave of anti-institutional sentiment, said Peter Ubertaccio, a Stonehill College political scientist.
“There’s not a lot of public trust in a whole slew of institutions, and political parties are not immune to that,” Ubertaccio said.
There are also a few less existential explanations. Massachusetts’ primary system gives unenrolled voters more options. They can walk into the voting booth on Election Day and choose which party’s primary they want to participate in. Registered Democrats and Republicans? They’re locked into pulling their party’s ballot unless they change their registration ahead of time.
Also a factor: a 2018 law that automatically registers eligible residents to vote when they get or renew their driver’s licenses, or join state health insurance. The law has pushed thousands of people on the rolls without a party designation.
If the broader trend away from party affiliation continues, there’s a chance it could eventually change more than just the registration numbers.
“I would expect to see more conversation about the way that we structure our election,” Ubertaccio said.
Case in point: the so-called all-party primary ballot question set to go before voters in November that would eliminate party primaries as we know it.
Matt Stout of the Globe staff contributed to this report.
Kelly Garrity can be reached at kelly.garrity@globe.com.
