State Attorney General Coakley and state Treasurer Steve Grossman tussle on several issues, while Don Berwick touts himself as candidate with fresh ideas at Stonehill College event sponsored by GateHouse and WCVB

EASTON — Treasurer Steve Grossman clashed with Attorney General Martha Coakley on a few occasions Tuesday night, while Don Berwick painted himself as the outsider.

The trio of Democratic candidates for governor discussed a wide array of issues at a forum hosted by the Joseph W. Martin Institute for Law & Society at Stonehill College in Easton. GateHouse Media and WCVB Boston co-sponsored the event. Voters will decide which of the three hopefuls emerges victorious from the Sept. 9 primary.

Each of the three favored universal pre-kindergarten in Massachusetts, and all were opposed to a ballot question that would repeal a law tying future gas tax increases to inflation.

Berwick was the only one of the three opposed to casino gambling.

“Casinos destroy communities,” he said.

He added that gambling often leads to further inequality.

Coakley said that, while casinos wouldn’t have been the first source of revenue she would have sought out, she doesn’t support a repeal.

Grossman said that Massachusetts residents are already going out of state to gamble, costing the state revenue.

“That $300 million in revenue, if you choose to use it for a single purpose, could pay for universal pre-k,” he said.

Grossman criticized Coakley’s handling of a case involving a lobbying firm accused of profiting from an inappropriate contingency fee with Franciscan Children’s Hospital. The firm, the Brennan Group, allegedly collected $370,000 from the hospital, overcharging the institution by $100,000.

Grossman said the firm, whose principal is a past campaign donor to Coakley, should have had to pay the full $370,000. The lobbying firm repaid $100,000, the amount it allegedly overcharged.

Coakley said the resolution was fair and said she has “always been transparent” about her donors.

“That’s why I’m against super PACs in Massachusetts,” she said. “We should know who is funding campaigns.”

The statement was an apparent reference to the Mass Forward Super PAC, which has collected and spent money to support Grossman. A new state law passed last month requires super PACs to disclose their donors.

The three candidates frequently referenced their backgrounds Tuesday night as they attempted to shape the narrative ahead of the Sept. 9 primary.

Coakley touted her record on public safety issues, while Grossman referred several times to his previous experience in the private business sector. Berwick, a doctor and former Medicare and Medicaid director, cast himself as a source of new ideas.

Rick Holmes of the MetroWest Daily News and MassPoliticalNews.com, Christopher Burrell of the Patriot Ledger and Janet Wu of WCVB served as panelists. Steve Kornacki of MSNBC moderated the forum.

Discussing medical marijuana, each candidate agreed that the state government has mismanaged the licensing process. Coakley and Grossman added that they would wait to see how things unfold in Colorado and Washington state before determining whether they would favor legalization of the drug for recreational use.

Responsible use of power was another topic Tuesday. The candidates discussed the recent indictment of Texas Gov. Rick Perry, accused of using politics as a motive in pushing for the resignation of a district attorney facing allegations of drunk driving.

“From what I’ve seen so far, he went too far,” Berwick said.

Grossman said Perry has to be deemed “innocent until proven guilty” but said, “Clearly, he was indicted, so, clearly, a group of his peers thought what he did was wrong and that he violated the law.”

Coakley said the indictment raises some “red flags” and suggested it may have been politically motivated.

The candidates also addressed the unrest in Ferguson, Mo., where a fatal police shooting of an unarmed black teenager was followed by massive demonstrations and clashes with law enforcement.

“I would hope that in Massachusetts, if an incident like that happened ... things would have been handled better at the outset,” Coakley said.

Coakley, touting her public safety background, said authorities in Missouri should have done a much better job investigating the shooting early on and sensitively sharing that information with the public.

Grossman pointed to Gov. Deval Patrick’s actions after the Boston Marathon bombings as an example of strong leadership in a time of crisis.

“I think Gov. (Jay) Nixon should have taken page out of Gov. Deval Patrick’s book,” he said, describing Patrick’s decision to remain visible and communicate with the public.

Berwick said he is “for community policing, not combat policing,” and called for an inclusive system for all.

Gerry Tuoti is the Regional Newsbank Editor for GateHouse Media New England. Email him at gtuoti@wickedlocal.com or call him at 508-967-3137.