With huge profits at stake, Suffolk Downs is flooding East Boston with flyers and Blue Line ads touting the casino it wants permission to build in the neighborhood. The company has spent nearly $1 million on its campaign already, according to city filings, and it’s obvious why: If voters approve the casino and the plan then wins the competition for a state license, it would be a bonanza for the ailing racetrack and its partner, Caesars Entertainment. But the electioneering demonstrates how unfair a vote can be when one side enjoys a vast financial advantage, and highlights the need for tighter campaign-finance restrictions as the state’s local casino votes near.

At the insistence of Governor Patrick, the Massachusetts casino law enacted in 2011 included a stipulation that a casino plan needs approval from the host community’s voters before it can be submitted to the Gaming Commission. Given the possible impact of a casino on traffic, crime, and quality of life, it’s a crucial provision.

For those votes to be meaningful, they need to be fair. But as campaigning gets underway in Springfield, Everett, East Boston, and elsewhere, casino corporations are outspending opponents by margins large enough to make a mockery of the process; in East Boston, for instance, No Eastie Casino reported $259 in cash contributions in 2012, less than what casino supporters reported spending just on balloons.

Before any referendum is formally scheduled, the state needs tighter ground rules. An East Boston lawyer, Ernani DeAraujo, has asked Suffolk Downs to submit to a spending limit of $500,000 for the rest of the campaign. The company should agree, and the backers of the other casino plans in Massachusetts should follow suit; $500,000 is more than enough to conduct a campaign. The companies should also agree to go beyond the existing disclosure requirements by listing all money they spend in the community, including charitable donations that don’t need to be disclosed on campaign finance reports but may serve to build support among neighborhood groups.

Ideally, Suffolk Downs and other prospective casino operators will agree to those rules voluntarily. But they may need some prodding from the gambling commission, which has the leverage to impose higher expectations on applicants. The commissioners should tell casino applicants that they will need to prevail in a fair and transparent vote to be considered for a license. And if Suffolk Downs or any other prospective casino operator lacks enough confidence in its plan to play by those rules, commissioners will need to wonder what they’re afraid of.