PHOENIX — The campaign over whether marriage should be defined — and limited — in the state constitution could soon start to look like a fight between two politically polarizing groups: gays and Mormons.

Those who want to define marriage as between one man and one woman will try to convince voters that without the constitutional amendment, courts could overturn Arizona's law banning on same-sex marriage and allow gays to wed, citing such an occurrence in California.

Meanwhile, opponents are crafting a strategy to label the amendment an attempt by the Mormon church to clean up its image after a series of polygamy scandals by fringe groups that are not actually affiliated with the church.

Backers of the amendment call that claim "religious bigotry" and a political "scare tactic," pointing to support from other denominations — although members of the Church of Jesus Christ of Latter-day Saints do appear to be providing much of the cash fueling the campaign.

The injection of two often uncomfortable subjects for some voters — religion and sexuality — into the public policy debate portends a campaign even more divisive than the 2006 battle over a similar, though much broader, amendment.

Arizona Together, which opposes Proposition 102, has begun framing the ballot referendum as a mostly Mormon-backed attempt to rectify what it calls a "polygamy problem" in the eyes of voters.

The opponents' argument against the ballot measure also rests on convincing voters that Mormons and other religious groups are seeking to "impose their views on people."

The leader of the campaign against the amendment is state Rep. Kyrsten Sinema, the openly bisexual Phoenix Democrat who led the successful opposition to the 2006 amendment.

Sinema, who was brought in after opponents struggled with how, and even whether, to fight the measure, is trying to drive home the idea that the amendment is unnecessary because of the state's existing legal ban on same-sex marriage, and that it's a repeat of the effort of two years ago.

"You can change the name, you can dress it up, but it's still the same thing," Sinema said in an interview. "There are many who believe it's offensive to tell voters they're stupid and ignore the pressing issues of the state."

But the measure on this year's ballot is significantly different from the one Sinema helped defeat in 2006 in that it would not limit unmarried couples' partner benefits offered by local governments.

With that change, the opponents lost their most effective campaign point from 2006, when they characterized the ban as an attack on opposite-sex couples who might lose benefits, while largely ignoring the potential effect on gay couples.

Past polling has shown that on the singular issue of marriage, Arizona voters support such an amendment. So opponents are trying to focus the discussion elsewhere, notably on the Mormon church.

Sinema said the ballot measure is a reflection of the Mormon church "working hard to convince the public that they are mainstream." She said her background, being raised Mormon in Tucson, gives her the credibility to make the charge.

"I don't think Arizonans are interested in having the Mormon religion dictate public policy to them," Sinema said.

Sinema contends that at least three-quarters of the individual donors to the campaign are with the Church of Jesus Christ of Latter-day Saints, based on her group having Googled donor names along with "LDS" or "Mormon."

While that method of verifying the religion of donors may be questionable, Sinema points to top backers with ties to the Mormon church: $100,000 from philanthropists Rex and Ruth Maughan, and $40,000 from Kristen Cowley, an organizer of the LDS Easter pageant.

Even if others are not pumping as much cash into the campaign, the cause is also backed by a list of churches and conservative groups outside of the Mormon faith, including Arizona's two Catholic bishops and the Union of Orthodox Jewish Congregations of America.

And Proposition 102 is on the ballot because of the efforts of a social-conservative lobbying group called the Center for Arizona Policy, an organization with evangelical roots — a segment of religion with which Mormons have had a complicated relationship.

Sinema rejected the notion that she might be trying to exploit any animosity between evangelicals and Mormons for political gain.

"They hate each other enough all on their own; they don't need any help from me," she said.

Michele Baer, spokeswoman for the campaign pushing the amendment, calls the focus on Mormons a "political scare tactic from the opposition."

But Baer — herself a Mormon singer — could not explain why voters would be scared of such involvement by Mormons.

"I don't know," she said. "I'm just saying that there is such broad-based support across all political, religious and ethnic backgrounds that support this proposition."

And Baer wouldn't comment on where the bulk of the funding is coming from, calling that "campaign strategy."

"I can't share," she said. "They can look at public records."

Baer called the initiative "20 simple and clear words that define marriage as the union of one woman and one man. It's pretty much that simple."

Asked why same-sex marriage should not be allowed, Baer answered: "We're not against anyone; we're for marriage.

"Marriage has been around since the beginning of civilization, and others can live how they choose, but they should not be allowed to redefine marriage for our entire society," she said. "This is a legacy we want to pass on to future generations in Arizona, and it isn't just a small group of people trying to do it."

State Rep. Kirk Adams, a Mormon Republican from Mesa, said Arizona Together's focus on Mormons "smacks of religious bigotry."

"It's important for me personally for this to pass, but polygamy has nothing to do with it, because polygamy has nothing to do with the Mormon church," he said. "Marriage between one man and one woman is a moral issue."

Adams said the level of involvement from the Mormon community is a reaction to a Supreme Court decision in California that essentially legalized gay marriage there.

"That, I think, was a watershed moment," he said.

Sinema said she isn't suggesting that individual members of the church are involved because of polygamy concerns. Rather, she said, that's the motivation of the Mormon church leadership. "The members do what they're told," she said.

She points to opposition to the amendment from some religious groups, and she said a press conference is slated next week in Tucson with religious leaders.

But while Sinema said the amendment is unnecessary because no one in Arizona is advocating for gay marriage, Arizona Together has received $50,000 — the bulk of its money so far — from the Human Rights Campaign, the largest gay and lesbian lobbying group in the country and one that supports marriage equality.

The group's Web site says, "When the California Supreme Court ruled that denying same-sex couples the right to marry is unconstitutional, we came one step closer to achieving true marriage equality for gay, lesbian, bisexual and transgender Americans."

Sinema said that's irrelevant, because the campaign will likely raise more money over the next two months, making Human Rights Campaign's involvement a small piece of the economic pie.

"I'm happy to take money from those groups," she said. "That's politics. Do I agree politically with all the people who donate to our campaign? Of course not."

How well Arizona Together does at getting its message out remains to be seen. With less than two months to go, it has raised $80,000.

The measure's backers have $3.34 million.

On StarNet: See more of Daniel Scarpinato's thoughts and stories at go.azstarnet.com/politicalblog.

● Contact reporter Daniel Scarpinato at 307-4339 or dscarpinato@azstarnet.com.