Maryland Gov. Martin O’Malley (D) really wants a deal to open a sixth casino in his state. So much so that he plans to unveil a draft bill for legislators to eyeball on Friday. His goal is to get it approved in a special session. And if that happens, then Maryland voters get the final say at the ballot box in November. It’s this prospect that has proponents of the state’s marriage-equality law very nervous.

O’Malley is a fervent proponent of marriage equality. He signed the Religious Freedom and Civil Marriage Protection Act in March, making Maryland the seventh state to legalize same-sex marriage. (The District has also done so.) But it doesn’t take effect until January. This gave opponents time to collect the necessary signatures to bring the law up for a popular vote this November. And it bears repeating that putting the rights of a minority up to a popular vote is wrong. Stripping rights from a minority is unjust.

So, what does this have to do with gambling? A lot, fear advocates.

O’Malley is pushing to get approval of a sixth casino in Maryland to be built in Prince George’s County and operated by MGM. Just as a point of information, Prince George’s County is majority African American and they make up a majority of voters there. But O’Malley has to get the state legislature to approve it in a special session called no later than mid-August. The state senate is on board. The governor’s obstacle has been the House of Delegates. And that’s only the beginning of the fight.

If past is prologue, the operators of the five existing casinos will fight like hell, including spending as much money as it takes, to defeat the MGM plan for Prince George’s. This is what happened when two of the companies with casinos in Maryland went head-to-head in Ohio over a 2008 ballot initiative to allow gambling in the southwest portion of the state. Lakes Entertainment of Minnesota (Rocky Gap Casino) spent $26 million in an effort to pass it. Penn National Gaming (Hollywood Casino) spent just shy of $38 million to defeat it. The measure was defeated by more than a million votes.

Now, imagine what could happen in Maryland when those two corporations, plus the other three operating in the state, go to battle to defeat the MGM casino. “Gambling overwhelms every issue in the state,” said Chrys Kefalas, former legal counsel to former governor Robert L. Ehrlich Jr. (R). Kefalas is openly gay and testified in favor of the marriage equality bill in February. “This is a big fight with the potential for collateral damage.” That collateral damage being not only the marriage-equality law, but also the Dream Act for Maryland.

A gambling ballot measure this November “will energize a base of opponents who would also vote against marriage equality at a time of soft support for marriage equality,” Kefalas told me. This last point flies in the face of recent polling we’ve seen. But Kefalas and others raise doubts about the rosy data showing growing acceptance of same-sex marriage in Maryland.

A May survey from Public Policy Polling showed that if the vote to uphold Maryland’s marriage-equality law were held today, it would pass with 57 percent of the vote. The same poll showed African American support jumping to 55 percent. This was especially significant as the survey was done after President Obama’s historic announcement of support for same-sex marriage.

But that poll was commissioned by Marylanders for Marriage Equality. More independent polls, albeit done before Obama’s declaration, show a closer result. A Post poll from January showed 50 percent in favor of same-sex marriage and 44 percent opposed. A Gonzales Research poll, also from January, put support at 48 percent and opposition at 47 percent. “I do not believe at all that this initiative is above 50 percent among likely voters,” a Maryland pollster who is closely following the marriage-equality referendum told me.

So, same-sex marriage boosters are worried about the potential for a perfect storm that could lead to the defeat of the state’s law. There’s the prospect of casino operators spending millions to put the kibosh on a sixth casino. This could gin up the anti-gambling base of opponents that Kefalas told me is comprised of rural voters and African Americans, who oppose gambling for religious reasons.

“Any campaign to defeat a new casino might entail dragging religious opponents to gambling out of the woodwork,” said Jeff Krehely, vice president for LGBT research and communications at the Center for American Progress. The Maryland pollster I talked with echoed this concern, saying that a gambling referendum “adds to a ‘this is against our values’ argument” among those more conservative voters.

Maryland is a state that has no competitive statewide races and won’t see much of the presidential race because it is a lock for President Obama. Because it is widely believed that support for marriage equality is not nearly as strong as we think, anything that pulls more conservative voters to the polls, for whatever reason, is seen as a threat to the law. With same-sex marriage never winning at the ballot box, advocates are right to be worried.