Rhode Island’s debate over gambling expansion may be dormant these days, but in Massachusetts, slot machines are once again the hot topic.

The Bay State has pondered adding slot machines to its four dog and horse tracks for years. Yet this year, a new governor and a seemingly insurmountable budget deficit have given gambling supporters renewed hope.

For Rhode Island, that could mean bad news.

The theory has long been that gamblers like what is close and convenient. For many Massachusetts residents, that means a quick ride to Lincoln Park or, for a smaller number of people, Newport Grand. But if slot machines are allowed in Massachusetts, those gamblers might spend their money there instead. After years of explosive growth, Rhode Island’s slot revenues have for the first time started to decline.

The state relies heavily on money from the slot machines — an estimated $255 million this year. If Massachusetts cuts into even a little chunk of that business, it could compound the state’s already precarious budget situation. Rhode Island now faces a $360-million deficit over the next 17 months and even bleaker predictions for future years.

“Lincoln Park and Newport Grand’s revenue decline is a preview of what could become a precipitous drop in the state’s third largest revenue stream if Massachusetts approves slots at its racetracks,” Clyde W. Barrow, director of the Center for Policy Analysis at the University of Massachusetts, Dartmouth, said as part of a new study on the region’s gambling trends.

Barrow found that Massachusetts residents made about 647,000 visits to Lincoln Park and Newport Grand last year, while Rhode Islanders made almost 1.4 million trips. That means that nearly a third of gamblers here live in Massachusetts.

Rhode Island officials — for now — are quietly sitting by the sidelines.

House Speaker William J. Murphy, D-West Warwick, has said repeatedly that a casino is not up for discussion this year. In November, more than 63 percent of voters rejected a plan by Harrah’s Entertainment and the Narragansett Indian Tribe to build a casino in the speaker’s hometown. But if Massachusetts moves forward with slot machines, Rhode Island’s perennial debate about expanding gambling could be rekindled.

“We said five years ago that with the threat of Massachusetts expanding gambling … that it would definitively be a drain on our industry here in Rhode Island,” Murphy said yesterday.

Will Massachusetts approve slot machines this year?

“I don’t know,” Murphy said, “but from the winds that are blowing south from Massachusetts it looks like it is an issue that’s gaining steam.”

Senate President Joseph A. Montalbano, D-North Providence, added: “We remain attentive as discussions progress in Massachusetts. … Any action taken by Massachusetts that could adversely impact Rhode Island’s [slot] revenues would be cause for concern for us.”

Gerald S. Aubin, the head of the Rhode Island Lottery, said that Massachusetts tracks would need large amounts of money and time to catch up with Rhode Island’s two gambling facilities. He said Lincoln Park and Newport Grand have years of experience running their operations.

“I don’t think there will be an impact for a significant amount of time,” Aubin said. “Lincoln and Newport have been operating since 1992… I think we’re only getting stronger and better at it.”

Spokeswomen for Lincoln Park and Newport Grand refused to comment on Massachusetts.

Both facilities have said in the past that their expansion plans will help them stay competitive.

For several years the owners of Massachusetts’ two dog and two horse tracks have pushed to introduce slot machines at their facilities. They make many of the same arguments made by casino supporters in Rhode Island: expanded gambling would put more dollars into the state coffers, create jobs and recapture some of the gambling dollars currently heading out of state.

After the November election, they saw a spark of hope in some comments made by newly elected governor, Deval Patrick.

Former Gov. Mitt Romney was opposed to slot machines. During this fall’s campaign, Patrick spoke in similar tones.

But within days of being elected, Patrick started to soften his stance, saying he would at least keep an open mind.

“I’ve said I’m deeply skeptical of slots. I’ve also said I’ve spent more time with opponents than proponents,” Patrick said after the election. “I’m going to make a final decision after I have heard thoroughly from both sides.”

Massachusetts faces an estimated $1-billion budget shortfall this year.

At this point, all Patrick has said is that he will study the issue further. But that has been enough to enliven slot supporters.

Long-time slot proponent Gary Piontkowski, who heads Plainridge Racecourse horse track in Plainville — 20 miles north of Providence, told the Boston Herald earlier this month that Governor Patrick appears more open to slots than his predecessor.

“We just think it’s 360 degrees from Mitt Romney,” he said.

The other Massachusetts racing facilities are Raynham-Taunton Greyhound Park in Raynham, Wonderland Greyhound Park in Revere and Suffolk Downs in East Boston.

Barrow, the UMass professor, said yesterday: “The mere fact that the governor said he’s at least willing to entertain the idea … has certainly put it at the forefront of the political agenda. This is the first time since 1999 that it’s been a front-burner political issue.”

State leaders now plan to weigh the potential economic benefits against the social impacts of additional gambling. Allowing slot machines could also possibly clear the way for federally recognized Indian tribes in the state to build casinos.

Rhode Islanders will recognize some of the players.

Earlier this month, two high-ranking Harrah’s executives — Jan L. Jones and David Satz — told The Journal they were in Boston monitoring the situation.

Gambling supporters have been buoyed by studies conducted by Barrow, who did work this summer on behalf of Rhode Island casino supporters. His current work is paid for by the university.

In the last few weeks, Barrow has released six surveys. He has asked if Massachusetts residents want a casino or slot machines. He has also looked at who gambles at Connecticut’s casinos, as well as who gambles at Rhode Island’s two facilities.

Barrow found that 53 percent of the 1,041 Massachusetts residents surveyed supported slots at the tracks, 29 percent were opposed and 18 percent undecided. The margin of error was 3.1 percent.

Maureen Moakley, chairwoman of the political science department at the University of Rhode Island, predicted after November’s unsuccessful casino referendum that if Massachusetts allows slot machines, Rhode Island would quickly approve a casino.

“There will be a complete turnaround,” she said at the time.

Ultimately, Rhode Island’s actions are likely to be linked to what Massachusetts does. And nobody is willing to take a guess now at what that might be.

“I don’t speculate on politics,” said the Lottery’s Aubin. “I might be in the gambling business, but I won’t bet on that one.”

smayerow@projo.com