That means election officials will have to handle well over a million mail-in ballots, if turnout is similar to what it was in the last presidential campaign — far more than they'd get from absentee ballots in a more typical election year.
Despite the unprecedented task, voters generally have faith in the integrity of the election: 79% of likely voters say they're "somewhat" or "very" confident that Massachusetts will have "free and fair" elections this fall.
There is a partisan split: Supporters of President Trump are more skeptical than those backing Democrat Joe Biden. But even a majority of Trump voters, 54%, say they're at least "somewhat" confident in the state's election process.
"I just think in this day and age, with the COVID and everything, I think a lot more people are taking the mail-in process more serious," said Chris Giroux, a 48-year-old from South Hadley who plans to vote for Trump. "There's a lot of people watching it now."
The president has consistently tried to erode voters' trust in an expanded vote-by-mail process.
"Absentee voting, great," Trump said at a news conference last week. "But this mail-in voting, where they mail indiscriminately millions and millions of ballots to people, you're never going to know who won the election. You can't have that."
In Massachusetts, ballots are not mailed "indiscriminately," in the way Trump describes; voters have to request them. Perhaps that's one reason Massachusetts voters in the WBUR survey say they are more confident in their own state's election process than they are in the presidential contest, overall.
As for being able to "know who won," the outcome of the presidential matchup in Massachusetts figures to be clear. Biden leads Trump, 61% to 27%, according to the WBUR poll, which was conducted by the MassINC Polling Group and has a margin of error of 4.4 percentage points.
Still, Secretary of State Bill Galvin acknowledged voting by mail does add some small measure of risk. He said his office will be extra vigilant.
"You're liberalizing the process to afford people the opportunity to vote by mail, and when you do anything like that, you're expanding the opportunity for people to abuse it, as opposed to somebody coming in and actually voting in person, where they can be seen," Galvin said. "But it's a risk we have to take. We have to protect the rights of voters to participate who otherwise might not."
There is, after all, a global pandemic that could deter some people from voting in person. The interest of enabling those voters to cast ballots from home far outweighs any slim chance of fraud, said Rep. Joe Kennedy, who is challenging Sen. Ed Markey in a Sept. 1 Democratic primary that, like the general election, is being conducted partly by mail.
"Forcing people across the commonwealth to choose between your health and your vote is a massive form of voter suppression," Kennedy said.
Markey also supports voting by mail and is encouraging supporters to use that option. In an online ad, he says voting by mail is "the safest way to vote."
Galvin noted completed ballots in the Senate race must be received by local election officials by primary day. A postmark by Sept. 1 is not enough for a ballot to count, so Galvin advises voters to mail early.
Alternatively, some voters can do what Anastasia Rudich of Shrewsbury is doing.
"I'm not going to put it in the mailbox. I'm going to bring it to the town hall," said Rudich, 67. "They have a drop box at the town hall."
Rudich said she is very confident in mail-in voting, but delivering her own ballot will help her feel even better about a new process.
This segment aired on August 12, 2020.