Throwing the landscape for casinos in Massachusetts into chaos, the state Supreme Judicial Court ruled on Tuesday that an initiative petition repealing the 2011 casino law is eligible for placement on the November ballot.

READ: SJC ruling

The ruling sets up an intense battle in the next few months over the future of casinos. While voters in a few cities have approved casinos, voters in several other communities have rejected applications from casino companies.

Casino proponents have argued that resort-style facilities will create needed jobs and new state revenues while giving Massachusetts residents gambling opportunities available in neighboring states. Opponents say casinos are a threat to the businesses where they would be located and will bring crime and increased addiction problems.

Attorney General Martha Coakley, who oversees certification of ballot questions, had rejected the petition’s eligibility for the ballot, arguing that developers looking to build casinos have an “implied contractual right” to action from the state gambling commission on their applications, which would be denied if the law was repealed. Coakley’s decision prompted advocates of repealing the casino law to take their case to the state’s highest court.

“We conclude that the Attorney General erred in declining to certify, and grant the requested relief so that the initiative may be decided by the voters at the November election,” Justice Ralph Gants wrote in the decision, which was unanimous.

In a statement, Secretary of State William Galvin, who oversees elections, said, “In light of today’s unanimous decision by the Supreme Judicial Court, I look forward to putting the casino law repeal initiative on the ballot.”

The initiative petition proposes bans on casinos, slot gambling, and abolishes pari-mutuel wagering on simulcast greyhound races.

“In sum, the abolition of casino and slots parlor gambling, and of parimutuel wagering on simulcast greyhound racing, whether by the voters or the Legislature, would not constitute a taking of private property without compensation from those licensed to engage in such gambling operations, and therefore an initiative calling for their abolition is not inconsistent with the right to receive compensation for private property appropriated to public use,” Gants wrote. “Instead, the possibility of abolition is one of the many foreseeable risks that casinos, slots parlors, and their investors take when they choose to apply for a license and invest in a casino or slots parlor.”

Coakley planned an 11:30 a.m. press conference in her office to take questions on the decision, but in a statement said she was “pleased” that the SJC had ruled on the matter.

“My office had conducted a legal review of this ballot question, but knew it would ultimately be decided by the Court. My office worked cooperatively with both parties to put this issue before the Court. Now, with today’s decision, voters will have the final say,” said the attorney general and Democratic candidate for governor.

Casino advocates for years fought unsuccessfully to push a casino legalization bill through the Legislature, with former House Speaker Salvatore DiMasi famously squashing Gov. Deval Patrick’s first push for a casino law.

After DiMasi resigned and was later convicted in a contract rigging corruption case, the tide for casinos turned abruptly.

Almost overnight, the House shifted in favor of casinos and the Legislature followed the lead of House Speaker Robert DeLeo, Beacon Hill’s leading proponent of casinos. In 2010, the odds for a casino law appeared strong but the movement was tripped up by an eleventh hour disagreement between Patrick and legislative leaders.

In 2011, the casino law was approved and since then the Massachusetts Gaming Commission has been vetting applicants. DeLeo was not immediately available for comment and an aide said he had a public event scheduled for Tuesday – DeLeo plans to attend a school groundbreaking ceremony at 12:30 p.m. in his hometown of Winthrop.

The commission has awarded a western Massachusetts casino license to MGM Springfield and a racino license to Plainridge Racetrack.

Gants wrote the court acknowledges the argument that the risk of abolition through the initiative petition could discourage applicants from moving forward, and if the initiative petition prevails, discourage future companies from seeking licenses “if the Legislature or the voters were again to legalize casino or slots parlor gambling,”

And in the opinion, the high court also acknowledged the argument that the initiative might affect companies outside of the casino industry viewing Massachusetts as a “reliable place to do business.”

“These arguments may properly be considered by the voters in deciding how to vote on the initiative, but they have no relevance to the determination whether the petition meets the legal requirements of an initiative and should be included on the November ballot,” the court wrote.

John Ribeiro, chairman of the Repeal the Casino Deal group behind the ballot initiative, said the more time that passes and the more people learn about casinos the less popular they become. Recent polling has shown conflicting levels of support for expanded gaming in Massachusetts and the repeal effort.

“While this ruling marks a huge hurdle now cleared, it’s also the firing of the starting gun in this incredibly important campaign,” Ribeiro said in a statement. “We know Massachusetts can do better than this casino mess. We’re elated at the opportunity to continue sharing the truth about casinos and the harm they would bring to our communities. Now’s the time to dig our heels in and spread our message.”

At the Democratic Party’s election-year convention this month, which was attended by many legislators who voted for the 2011 law, Ribeiro collected signatures for the repeal petition and said he sensed strong support for it.

The court’s decision will reverberate through the ongoing campaigns for statewide office. Republican frontrunner for Gov. Charlie Baker immediately took to Twitter to question Coakley’s judgement.

“I never got why AG Coakley thought this issue didn’t belong in front of the voters. Glad the SJC thought otherwise,” Baker posted online.

After chairing a Lottery Commission meeting, state Treasurer Steven Grossman, a Democratic candidate for governor, said he will vote no on the casino repeal ballot question, but thinks the SJC made the right decision in giving people the chance to decide. Grossman told the News Service he has long-supported casino gambling in the state because of the jobs it will bring.

“As you know, like Governor Patrick, I have supported the expansion of casino gambling in Massachusetts because it holds the prospect of creating 15,000 good jobs. We’re still a couple hundred thousand people out of work. Those are 15,000 people who could be put to work and work for a long, long time. I’ve supported it, primarily based on its job creation potential,” Grossman said.

“Personally, I’ll vote against repeal,” Grossman said shortly after the court ruled. “But I think it was entirely the right decision and I’m delighted the SJC decided to put it on the ballot.”

Don Berwick, a Democrat running for governor, said he was “delighted” by the court’s decision.

“Casinos are a bad deal for Massachusetts. Where they come, small businesses suffer — the evidence is that they destroy one local job per slot machine. They bring gambling addiction, increased substance abuse, DUI risks, and other safety problems into our communities,” Berwick said in a statement. “The promises of new state revenues are greatly exaggerated, and state expenses will have to rise to repair the damage casinos will do. I am glad that Massachusetts voters will have the opportunity to make their voices heard on this important matter. I am confident that the repeal initiative will succeed.”

Former assistant attorney general Maura Healey, a Democrat running for attorney general, called the state’s foray into expanded gambling “a mess” that has become “embroiled in conflict, controversy and potential corruption.”

“The SJC made the right call on the facts and for history. Casinos are bad economic policy and I strongly support repeal,” said Healey, whose primary opponent Warren Tolman does not support repeal.

Meanwhile, Democratic candidate for lieutenant governor Stephen Kerrigan said he would vote against repeal, noting that the issues were debated in the Legislature for years before being passed “overwhelmingly” in both the House and Senate and signed by Gov. Patrick.

“We, as a Commonwealth, should be very cautious before using this method to overturn a broadly-discussed and widely-accepted economic development plan nearly three years into its implementation. Changing course now on gaming would send the wrong message to the business world about the stability of our economic development process and the predictability our political system,” Kerrigan said in a statement.

Kerrigan said repeal would particularly impact places like Springfield, where civic leaders have spent time, energy and resources to plan around the MGM casino that received the first license of its kind in Massachusetts and where local voters endorsed the project. He said the state’s focus should be on implementation of the gaming law.

Colleen Quinn contributed reporting.