Sen. Elizabeth Warren (D-Mass.) questions Wells Fargo’s chief executive during his testimony before the Senate Banking Committee in Washington on Sept. 20. (Gary Cameron/Reuters)

There is a pitched battle underway in Massachusetts over charter schools, with proponents pouring money into an initiative on the November ballot that would raise the state cap on their growth and opponents arguing that charters are draining resources from traditional public schools. Now critics have gotten a big boost: Sen. Elizabeth Warren said she was going to vote against Question 2.

Warren, who has been viewed somewhat warily by many public-education activists because of her past support for charter schools, now says she does not support unfettered charter growth in Massachusetts because local school districts can be harmed. Just a few weeks ago, local media noted that Warren, highly popular in Massachusetts, had not declared her position on the charter cap.

There are now nearly 80 charter schools in Massachusetts, where no more than 120 charter schools are currently allowed to operate. Question 2 would allow 12 new or expanded charter schools to open every year anywhere in the state, a move that supporters say will give more parents choices about where to send their children to school and help close the achievement gap. Critics say that charters typically underserve the highest-needs students, are not accountable to the local communities in which they are located and end up hurting students in traditional schools.

Dozens of local school districts have taken positions against raising the cap even as supporters have flooded Massachusetts with millions of dollars from inside and outside the state to run pro-charter ads that are being produced by a firm that made the now-infamous “Swift Boat” ads in 2004 against then-Democratic presidential candidate John F. Kerry.

Warren released a statement to the Boston Globe that said:

“I will be voting no on Question 2. Many charter schools in Massachusetts are producing extraordinary results for our students, and we should celebrate the hard work of those teachers and spread what’s working to other schools. But after hearing more from both sides, I am very concerned about what this specific proposal means for hundreds of thousands of children across our Commonwealth, especially those living in districts with tight budgets where every dime matters. Education is about creating opportunity for all our children, not about leaving many behind. I hope that the Legislature, the teachers, and the parents can come together to find ways to make sure all kids in Massachusetts get a first-rate education without pitting groups against each other.”

Though Question 2 has both Republican and Democratic supporters, Maurice Cunningham, a professor of political science at the University of Massachusetts at Boston and a longtime commentator on state politics, said that the initiative’s big funders are mostly Republicans. Here’s part of an interview he did with Jennifer Berkshire, a freelance journalist and public education advocate, for her blog, Edushyster:

EduShyster: There’s a well-funded effort underway to paint the campaign to lift the charter cap in Massachusetts as a progressive cause. But what you’ve found in your research is that this is basically a Republican production from top to bottom.

Cunningham: That’s right. There are a handful of wealthy families that are funding this. They largely give to Republicans and they represent the financial industry, basically. They’re out of Bain, they’re out of Baupost, they’re out of High Fields Capital Management. Billionaire Seth Klarman, for example, has been described as the largest GOP donor in New England, and he gives a lot of money to free market, anti-government groups. Then on the campaign level, you have Republican strategist Will Keyser who certainly knows his stuff, and Jim Conroy who certainly knows his stuff. They know how to make something look like a grassroots campaign that really isn’t.

EduShyster: By *make something look like a grassroots campaign that really isn’t,* what you really mean is that this is an entirely community-driven, grassroots campaign, correct?

Cunningham: No. There is no grassroots support behind this campaign whatsoever. What do we look for to measure grassroots support? We look for a campaign’s ability to find people who will essentially volunteer, who feel strongly about an issue and are willing to do the work that a campaign needs done. Two examples: signature collecting and canvassing door to door. Great Schools Massachusetts isn’t able to do either one of those things. When they had to get signatures in 2015, they wound up paying $305,000 to a signature gathering firm. And that’s because they don’t have people who are strong believers who will go out on the street and volunteer and be passionate and do the things that people do when they really care about an issue. Or look at Democrats for Education Reform. When they backed Dan Rizzo in the special Senate election earlier this year, they had to pay for canvassers because they don’t have people who feel strongly enough about the positions they take. The idea that these are community groups is completely manufactured.

If Question 2 passes in November, it will take effect in January 2017. A WBUR poll of likely voters taken a few weeks ago found that 48 percent would vote against lifting the charter cap, 41 percent would vote to lift it, and 11 percent hadn’t decided.