The casino referendums are over in York County. But the battle will continue for the next year on whether to legalize casino gambling in Maine to pave the way for two Indian tribes to build a casino-resort in Sanford.

Casino supporters breathed easier on election night after Sanford residents approved a nonbinding referendum in support of casino gambling. Gaining the approval of a York County community was a sizable obstacle for casino supporters to overcome in their quest to build a half-billion-dollar casino showcase in southern Maine.

The casino battle has already taken on the tone of a political campaign, with political action committees, behind-the-scenes strategizing and biting rhetoric. On Wednesday, casino critics demanded that casino backers withdraw their plan to bring “hard-core casino gambling” to Maine.

Mark Robinson of the Casinos No PAC said his group would step up fund-raising efforts, expand its grass-roots network and continue to hammer away at casinos. He expects casino backers to launch an advertising campaign next fall that will be unprecedented in Maine history.

“The sheer volume will take your breath away,” he said.

Erin Lehane, spokeswoman for the Think About It pro-casino PAC, agreed it will be a heated battle when Mainers are asked to legalize casino gambling. She said supporters would do whatever it takes to deliver their message of jobs, economic development and tax revenues to every Maine resident.

“We’re going to explore every medium to reach every voter,” she said.

The Passamaquoddy and Penobscot Indian tribes have proposed building a casino and resort in southern Maine that they say will generate more than $100 million a year in tax revenues.

A slew of York County cities and towns have held nonbinding referendums in recent months asking residents whether they favor casinos in their communities or in the state. Casinos are now illegal in Maine.

Voters rejected casinos in all municipalities – except Sanford, where residents Tuesday voted in favor of them 55 percent to 45 percent.

Sanford is a hardscrabble city where jobs come and go, and unemployment – 7.3 percent in September – is nearly double the rate of York County. That helps explain why Sanford residents voted to accept a casino while neighboring towns were rejecting them by overwhelming margins.

Residents couldn’t ignore a study indicating a casino would create more than 4,000 jobs with an average salary of $31,400, Sanford City Administrator John Granfield said.

“In our town, that would be considered excellent employment,” he said.

Casino organizers are continuing to collect the estimated 50,000 signatures they need to force a statewide vote on the question: “Do you want to allow a casino to be run by the Passamaquoddy Tribe and Penobscot Nation if part of the revenue is used for state education and municipal revenue sharing?”

Lehane said more than 40,000 signatures have been collected. They must be delivered to the secretary of state’s office by Jan. 23.

Casino supporters are also looking at property in the southern end of Sanford that might be appropriate for a casino. The south end of the city is desirable because it has large tracts of undeveloped land, is only seven miles from the Maine Turnpike and is near Sanford Regional Airport.

Lehane said a casino complex may need hundreds of acres to accommodate a casino, a hotel, a theater, a convention center, a golf course, retail stores, restaurants, nightclubs and other services.

Robinson said the casino issue is about to transform from a regional to a statewide issue.

He said casino backers are pushing the issue at a time when Maine may be susceptible because of the stagnant economy and the state budget shortfall.

“You have to step back and take a global view,” Robinson said. “Las Vegas wants into Maine, and they’re striking at our most vulnerable time.”