A leading charter school supporter on Tuesday accused the state’s local officials of failing to adequately educate all students, at a tense and fast-moving debate on a ballot question that would allow for the creation or expansion of up to 12 charter schools per year.

“It is local control that got us into this situation that we’re in, where tens of thousands of children are being left behind by their local district schools,’’ said Marty Walz, a former Democratic state representative, fending off a question about the large number of corporate and financial executives who sit on the boards of Massachusetts charter schools.

“The reason charter schools exist is because local school districts have wholly failed to educate far too many children in this state,’’ Walz said at the debate, which featured an audience of partisans hissing and clapping at various points.

The hour-long forum, which was sponsored by WBUR, the Boston Globe, and UMass Boston’s McCormack Graduate School of Policy and Global Studies, covered issues of race, funding, and academic performance and often featured a blizzard of competing statistics.

Heated but respectful, it laid bare how charged the charter-school fight has become ahead of the November election.

Tito Jackson, a Boston city councilor who opposes Question 2, argued that charter schools drain money from traditional schools, which he said are educating more of the most challenging students, including those who are homeless and do not speak English fluently.

“We need those resources to close that achievement gap,’’ he said.

The debate came as a new survey by WBUR and MassINC Polling Group showed that 48 percent of likely voters oppose Question 2, while 41 percent support it. About 11 percent are undecided.

The debate was the first of four forums that will address the November ballot questions.

All will be held at the McCormack Theatre on the UMass Boston campus.

The other proposals would allow for a second slots parlor in Massachusetts, require more humane conditions for some farm animals, and allow anyone 21 years or older to buy marijuana, distribute it, and grow it at home.

The charter school battle is expected to break spending records for ballot campaigns, with both sides expected to pour a total of at least $18 million into the fight.

Teachers’ unions are largely bankrolling the opposition, while business-backed groups have spearheaded the move to expand charters. Some of those groups are nonprofits that do not, under state law, have to disclose their funders, allowing the individuals backing the effort to remain anonymous.

Walz argued that focusing on the anonymous donors was a distraction from the positive results charter schools have achieved. A 2015 Stanford University study, for example, found that Boston charter school students outperformed their counterparts at traditional public schools and at charter schools in other urban areas by a striking margin over a recent six-year span.

“The debate really should be about who’s doing the best job educating children, as opposed to the adult concerns about who’s donating to the campaign,’’ Walz said. “We should be about kids, not the adults.’’

But pressed by Meghna Chakrabarti, the host of “Radio Boston,’’ who moderated the debate with David Scharfenberg, a Globe political reporter, Walz said she welcomed the out-of-state financial support, despite the criticism that much of it is untraceable “dark money.’’

“We’re delighted when anybody wants to step up and support our efforts,’’ Walz said. “The more help we get educating all our kids in this state — that is all to the good.’’

Both sides also sparred over the funding for charter schools.

Under state law, when district school students leave for charters, they take with them a portion of state aid, and the district school is given a multiyear reimbursement to help it adjust to the loss of funding.

Walz argued that it makes sense for the money to follow the student and said Boston Public Schools have no right to continue receiving state aid for students they are no longer educating.

“This is money allocated from the state to educate children in the public schools – both district schools and charter schools,’’ said Walz, former House chairwoman of the Legislature’s Education Committee. “It’s not just to go to Boston Public Schools and fund its bureaucracy.’’

She blamed budget problems in the Boston Public Schools on bloat and inefficiency in the system, which she said is designed to educate 93,000 students, not the 57,000 currently enrolled.

“Boston is not right-sizing its budget,’’ said Walz.

Jackson disputed the claim that Boston has thousands of unused seats and said the 100 School Committees statewide that have lined up in opposition to Question 2 show that concerns about the loss of funding are real.

“If this funding was actually going to help all students, then I would be absolutely for it,’’ said Jackson, a Roxbury resident. “It absolutely doesn’t help all students. It detracts from the funding for public schools.’’

Michael Levenson can be reached at mlevenson@globe.com. Follow him on Twitter @mlevenson.