Pam and Rick Patterson have always followed teachings of the Church of Jesus Christ of Latter-day Saints and tried to live within their means.

He drives a 10-year-old Honda Civic to his job at Intel. She is a stay-at home mom who makes most of the family meals and bakes her own bread. The couple, who have five sons between the ages of 3 and 12, live in a comfortable but modest three-bedroom home in Folsom.

It's a traditional lifestyle they believe is now at risk. That's why the Pattersons recently made a huge financial sacrifice – they withdrew $50,000 from their savings and donated it to the Yes on Proposition 8 campaign, the ballot measure that seeks to ban same-sex marriage.

"It was a decision we made very prayerfully and carefully," said Pam Patterson, 48. "Was it an easy decision? No. But it was a clear decision, one that had so much potential to benefit our children and their children."

Mormons such as the Pattersons have emerged as the leading financial contributors to the controversial Nov. 4 ballot measure. Church members have donated about 40 percent of the $22.8 million raised to pass the initiative since July, according to Frank Schubert, campaign manager for ProtectMarriage.com, the primary backer of the "yes" campaign.

Other religious groups have contributed, including a Catholic fraternal service organization – the Knights of Columbus – which donated more than $1 million. But no group has given more than the Mormons.

In a June letter to members, top church leaders urged them to "do what you can do" to support Prop. 8. Members have answered the call.

Mormons have sponsored meetings, knocked on doors, installed lawn signs, staffed phone banks and given generously.

Their financial dominance is getting their opponents' attention and raising concerns about the role of churches in state policymaking.

"I think anyone would be troubled by any one religion exerting that kind of financial influence in a decision about what our constitution is going to say," said Kate Kendell, executive director for the National Center for Lesbian Rights and a member of the executive committee of No on Prop 8.

"The amount of money the Mormon church is giving is alarming and sobering," she said. "This is a wake-up call."

Kendell said there are a number of people of faith who oppose the ban and who are working to defeat Prop. 8. "There is not one monolithic view on this, but surely this is a case where we're being massively outspent," Kendell said.

Opponents have raised about $17 million since July, according to Kendell.

She believes reports about the financial role Mormons are playing will motivate opponents of the measure. "Too many people are sitting on the sidelines," she said.

Several celebrities have made generous donations, including film director Steven Spielberg and T.R. Knight of the television series "Grey's Anatomy," who each gave $100,000.

"But we're not going to win with celebrity money," Kendell said. "We need everyday Californians who are willing to write checks and make the financial sacrifice for their beliefs."

Churches can play an active role and can endorse propositions without violating federal tax laws, according to Robert Boston of Americans United for Separation of Church and State.

"Those laws prohibit churches from endorsing or opposing candidates," said Boston. "That principle does not extend to the discussion of an issue. They are allowed to address ballot issues."

Mormon officials contend that this "is not a Mormon issue. And it shouldn't be portrayed that way," said Lisa West, spokesperson for the church in the Sacramento region.

More than 700,000 church members live in the state; 85,000 in the Sacramento region. "Obviously, a lot of other people besides Mormons are concerned about this and are contributing," she said.

West said church members have given generously to this issue because it strikes at the core of their beliefs – that marriage is between a man and a woman and lasts for eternity.

"The No. 1 reason members are donating and working toward this cause is the preservation of the traditional family," she said.

That's why Auburn resident David Nielson, 55, is giving. He said the church has not pressured him to contribute.

"Absolutely not," said Nielson, a retired insurance executive. He and his wife, Susan, live on a budget. The couple donated $35,000, he said, "because some things are worth fighting for."

The couple will forgo a vacation for the next two years and make other sacrifices to pay for their donation, he said.

"If it doesn't pass, then at least I can tell my grandchildren I gave everything I could," Nielson said.

The Pattersons, who have been married 14 years, say there were thinking about their children's future when they decided to tap into their savings to contribute. And they also said no one pressured them into giving.

They were reluctant to talk about their donation – not even their families knew how much they contributed – and agreed to do so only because it is listed on public campaign documents.

"The amount may surprise people," said Rick Patterson. "But people who know us, know how much the family means to us."

Will they regret donating so much of their savings if the ballot proposition fails?

"No. I feel totally at peace about it," Pam Patterson said. She said they will continue to live frugally. "We have done what we feel is right."

Call the Bee's Jennifer Garza, (916) 321-1133.