ANNAPOLIS, Md. » In the roiling state-by-state war over same-sex marriage, the campaign against marriage rights has been masterminded largely by one man.

Frank Schubert, a former corporate public relations executive, ran the $40 million, come-from-behind push for Proposition 8 in California in 2008. He went on to mount successful campaigns to defeat same-sex marriage in Maine and North Carolina. Now, with marriage initiatives on the ballot in Maryland, Minnesota, Washington state and Maine, Schubert is the chief strategist in all four at once.

Gay rights leaders despise Schubert, who has devoted himself to the issue in recent years, for what they call his misleading arguments. They have also learned to fear him for messages that are less openly harsh than those voiced by many other opponents of gay rights: a strategy aimed at reassuring the moderate voters who decide such elections that barring gays and lesbians from marriage does not make them bigots.

Citing polls showing growing public acceptance and armed with more than $25 million, gay rights leaders hope to win their first ballot victory for same-sex marriage on Nov. 6. But they are bracing for a rush of Schubert-designed television ads in the four contested states.

"Everyone has a right to love who they choose," says an ad now running in Minnesota, "but nobody has a right to redefine marriage."

Telling voters they are not prejudiced if they vote against same-sex marriage is "diabolically smart and creative," said Fred Sainz, vice president for communications of the Human Rights Campaign, a national advocacy group for gay rights. "He is putting lipstick on the pig of discrimination."

For his part, Schubert, who has a lesbian sister raising two children in a domestic partnership, says, "It’s hurtful to know that many people think I dislike gays and lesbians and wish them harm."

He spoke during an interview here in Maryland’s capital, where he was making last-minute tweaks to television ads and meeting with local organizers in what seems likely to be a close race.

Schubert expects to spend some $12.5 million overall, with one-third of the total provided by the National Organization for Marriage, the largest private group financing campaigns against same-sex marriage. In Minnesota, the Catholic Conference is providing $1 million.

His opponents have raised $25 million so far, a tally that includes $4.4 millionfrom the Human Rights Campaign and a donation of $2.5 million inWashington state from the Amazon founder Jeff Bezos and his wife.

In the six states that permit it, and the District of Columbia, same-sex marriage was mandated by courts or approved by the Legislature. But every time the issue has been on the ballot, in 32 states in a row, voters have come out against same-sex marriage. (Thirty states have constitutional amendments defining marriage as solely between a man and a woman, and another 11 have laws restricting marriage).

"If the other side succeeds this fall, I’m certain that it will open up a whole new front," Schubert said, predicting that groups in California, Oregon and elsewhere would be emboldened to bring forth public referendums.

Schubert, 56, attended Catholic schools in Sacramento, Calif., where he still lives with his wife. At age 22, he was chief of staff to a Republican assemblywoman. He entered public relations and became known, in the world of political consultants, for winning dozens of issue-oriented ballot campaigns on behalf of corporations: defeating proposals to increase tobacco taxes and to require restaurants to offer health insurance to employees.

He had not thought much about the marriage issue, he said, before he was tapped in 2008 to run the Proposition 8 campaign, which was mounted by religious conservatives to override the California Supreme Court decision permitting same-sex marriage. With a budget of $40 million, more than matched by opponents, he mounted a campaign with button-pushing ads.With that victory, Schubert won national attention, and his life took a sharp turn.

"The more I learned about the marriage issue, the more committed I became," he recalled.

He threw himself into the cause, teaming with the National Organization for Marriage, which pays him a retainer for strategic advice. Brian S. Brown, the organization’s president, praised Schubert in an interview as "the best in the business."

This year, as his activism began to turn off corporate clients, Schubert left Schubert Flint Public Affairs, the consulting firm he founded in 2003, and started a new one, Mission: Public Affairs, which he says will be entirely devoted to social causes.

"I think God has a plan for our lives," Schubert said of his shift. While the new focus is not as lucrative as corporate work, he continues to do well, receiving monthly fees of $10,000 to $20,000 from each of the four state campaigns and earning a commission on the voluminous ads he places on radio and television.

Schubert said that while he tailors messages to each state, certain themes have proved effective: that marriage between a man and a woman is the tested foundation of a stable society, that children do best when raised by a married father and mother and that "it is possible to respect the rights of gays and lesbians without redefining marriage."

"This is a difficult argument," he said, "because it sounds as if we’re saying gay couples can’t have loving relationships or care for children, which is not the case."

Gay rights leaders counter that they are not seeking to redefine marriage but to end discrimination. They say that the claims about child-rearing are unfounded and that while Schubert may profess a lack of personal prejudice, his sponsors have often vilified homosexuals.

"They’re trying to soften the rhetoric as it becomes clear that our society now frowns on being openly antigay," said Sainz of the Human Rights Campaign.

In each of the four states, Schubert is working with a local team that will mount the "ground game," mobilizing volunteers to knock on doors and run phone banks. He creates the advertising and approves the message.

Here in Maryland, the Rev. Derek McCoy is chairman and daily supervisor of the campaign to overturn, in a referendum, the Legislature’s adoption of same-sex marriage this year. At the recent meeting, Schubert and McCoy nodded approvingly as staff members described enlisting more Hispanic pastors and Seventh-day Adventists.

Conservative black pastors like McCoy have led the battle against same-sex marriage in this state, where Democrats dominate and more than 20 percent of voters are black. But securing the minority vote became more complicated when President Barack Obama and the NAACP both endorsed a broadening of marriage rules.

McCoy said that in his experience most blacks remained firmly opposed.

"I tell people that it’s fine if you want to vote for the president," he said, "but vote what you feel on marriage."

Schubert already has his eye on the next year or two, when he sees marriage battles brewing in Rhode Island, New Jersey and several other states. And he is talking with potential clients about campaigns to protect religious liberty and fight abortion.

But for now, he knows, the task is to extend that unbroken record of ballot victories in four states where, he notes, gay rights advocates are sure to outspend him.

"To be sure, these are all deep blue states, so no doubt we have a challenge," he said. "That said, at 32-0, I still like my chances."