Voter Marla Pyle fills out a ballot at an early voting location on Oct. 24 in Worcester, Mass. (Steven Senne/AP)

Fights over charter schools have become commonplace, but the one being waged right now in Massachusetts — which has long had as fine a public education system as any state in the country — isn’t your ordinary battle.

Question 2, an initiative on Tuesday’s ballot to approve the raising of the state’s cap on charter schools, is the most expensive ballot initiative in the country — with at least $35 million reportedly raised by both sides — and it’s been as bitter as any. The campaign in support of Question 2 seemed sure to be a success when it started, enjoying bipartisan support, but as time went on, opposition grew.

And now, whatever happens on Tuesday in Massachusetts could affect the national fight over the growth of charter schools. Supporters of charter schools say they give parents more educational choices for their children, while critics say they drain resources from traditional public schools, typically under-serve the highest-needs students and are not accountable to the local communities.

There are nearly 80 charter schools in Massachusetts, some of them among the highest-achieving schools in the state. Massachusetts has capped the total number at 120 charter schools, but Question 2 seeks to raise that cap, allowing the state to authorize 12 new or expanded charter schools to open every year, effectively blowing the idea of a cap.

The maneuvering over Question 2 has brought all of the elements we’ve come to expect in charter wars: big money from outside the state; concerns about the use of “dark money”; Wall Street involvement; charges of arrogance from both sides; a nasty advertising campaign, marked by pro-charter ads created by the firm that made the infamous “Swift Boat” 2004 ads against then-Democratic presidential candidate John F. Kerry; and a split among Democrats about the virtues and drawbacks of more charters.

President Obama hasn’t weighed in, but his secretary of education, John B. King Jr., did, telling the Boston Globe that if he lived in Massachusetts, he would vote “yes.” Obama’s former secretary of education, Arne Duncan, supports it too, as does the Democrats for Education Reform advocacy group. The Boston Globe’s editorial board agrees, as does Republican Gov. Charlie Baker, who said in a pro-charter ad: “Imagine if your kid was trapped in a failing school. Public charter schools give parents a choice and are a pathway for these kids.”

But the opposition is strong, too. Dozens of local school districts have come out against the initiative, as has the Massachusetts Parent Teachers Association. Massachusetts Sen. Elizabeth Warren opposes Question 2, saying in a recent statement that while “many charter schools in Massachusetts are producing extraordinary results for our students,” she is concerned that traditional public schools could be harmed and is voting against Question 2. Sen. Bernie Sanders of Vermont said in a statement that hedge fund managers and others have put millions of dollars into the pro-charter campaign and that “Wall Street must not be allowed to hijack public education in Massachusetts.” Boston Mayor Marty Walsh, a longtime charter supporter and the founding member of one charter, is opposed to Question 2, saying in a Globe op-ed:

Over time, it would radically destabilize school governance in Massachusetts — not in any planned way, but by supersizing an already broken funding system to a scale that would have a disastrous impact on students, their schools, and the cities and towns that fund them.

This impact would hit Boston especially hard. Twenty-five percent of statewide charter school seats, and 36 percent of the seats added since 2011, are in Boston. Each year, the city sends charter schools a large and growing portion of its state education aid to fund them. This funding system is unsustainable at current levels and would be catastrophic at the scale proposed by the ballot question.

The U.S. charter school movement began some 25 years with the idea that publicly funded but privately run schools would force failing traditional public schools to improve and eventually not be needed. The movement became popular with billionaire philanthropists, some of them seeing an opportunity to privatize public education and imprint free-market principles on the country’s most important civic institution. While some charters did a fine job of educating kids, others didn’t, and it became clear that the competitive model wasn’t going to work as planned. The rationale for charters began to change: They gave families whose children were trapped in failing urban schools an opportunity to have a choice.

Now charter schools enroll some 6 percent of the nation’s schoolchildren, and there are battles in many states about their growth and concerns, including whether they worsen segregation, rob traditional districts of cash, toss out students they don’t want, under-serve the highest-needs students, and in some states allow for-profit entities to make money off public funds.

The charter sectors in a number of states — including California, Ohio, Nevada and Arizona — are severely troubled, allowed to grow quickly with little or no oversight.  The charter movement, however, has failed to seriously address some of the most egregious problems in various state laws governing charters. Many of the biggest charter scandals involve those by for-profit entities and cyber charters. Massachusetts doesn’t allow either, and its charter schools are largely viewed as successful, yet still opposition to Question 2 has grown, including among strong charter supporters.

As a result, a “no” vote on Question 2  may force the broader charter movement to address some of the concerns, seek more accountability for charters and try to work with critics rather than to simply fight for charter autonomy at any cost.

Among the central issues in the Massachusetts debate is money: the amount being spent on the campaign and the way traditional districts are affected by charters. The Globe reported on emails sent by Moody’s Investors Services to four cities warning that their financial standing could weaken if Question 2 passes, but the firm would not officially discuss the emails.

Yawu Miller, managing editor of the Bay State Banner, which has been covering news in Boston’s African American and Latino communities since 1965, said in an interview with Jennifer Berkshire on the EduShyster blog:

People don’t want to see the existing district schools, some of which are struggling, some of which are doing remarkably well, harmed by charter expansion. And it has started to seem like charter schools are seeking to expand at the expense of district schools — like there’s an intent to displace the public schools.

Meanwhile, there has been a lot of concern among Question 2 critics about where supporters are getting their money. David Sirota, senior editor for investigations at the International Business Times, and an investigative team reported that teachers’ pension funds in Massachusetts are being used by Wall Street financiers to push Question 2. The International Business Times said:

When Massachusetts public school teachers pay into their pension fund each month, they may not realize where the money goes. Wall Street titans are using some of the profits from managing that money to finance an education ballot initiative that many teachers say will harm traditional public schools.

An International Business Times/MapLight investigation has found that executives at eight financial firms with contracts to manage Massachusetts state pension assets have bypassed anti-corruption rules and funneled at least $778,000 to groups backing Question 2, which would expand the number of charter schools in the state. Millions more dollars have flowed from the executives to nonprofit groups supporting the charter school movement in the lead-up to the November vote. Republican Gov. Charlie Baker, himself a former financial executive, is leading the fight to increase the number of publicly funded, privately run charter schools in Massachusetts — and he appoints trustees to the board that directs state pension investments.

Randi Weingarten, president of the American Federation of Teachers, which opposes the ballot measure, told the newspaper that this is a “morally bankrupt situation.”

More than $35 million has been raised in total by both supporters and opponents, according to MassLive.com, with pro-Question 2 forces raising $23.6 million and opponents raising $14.1 million.

The bulk of the money in support of Question 2 comes from a New York-based pro-charter group called Families for Excellent Schools, which donated $15.6 million — but, as a nonprofit group, is not required to disclose its donors. The money is being moved through a group called Great Schools Massachusetts. Also donating close to $2 million collectively are Jim Walton and Alice Walton of the family that owns Walmart and lives in Arkansas. Most of the money behind the push against Question 2 comes from national, state and local teachers unions, which, according to political scientist Maurice Cunningham, helped drive the pro-Question 2 money push. Cunningham is an associate professor at the University of Massachusetts at Boston who tracks dark money.

In an interview with Berkshire, Cunningham noted that “a handful of wealthy families,” largely Republican who represent the financial industry, are behind the pro-Question 2 funding.  He said:

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, antigovernment groups. … They know how to make something look like a grass roots campaign that really isn’t.

If Question 2 passes, it will take effect in January.

(Correction: Fixing name of Parent Teachers Association. Earlier version said Parent Teachers Organization.)