Diaz says he has received death threats because of his stance against same-sex marriage, but he proudly refers to his efforts as "a calling." Despite those efforts, the conservative Democrat says he gets along just fine with his gay brother, nephew and granddaughter.

"We have a very loving family," he says. "I love them. They love me. We help each other. They know that this is the Bible -- this is what I preach."

Perkins: 'Collateral Damage to Other Freedoms'

For a man who just turned 50, Perkins has been a conservative warrior most of his adult life. The issue of gay marriage is just the latest battle.

A former Louisiana politician, police officer and TV reporter, Perkins lost a race for the U.S. Senate in 2002. He became president of the Family Research Council the following year.

In 2008, Perkins called California's Proposition 8 more important than the presidential election. In 2010, he opposed doing away with the military's "Don't Ask, Don't Tell" policy. Last year, a man upset by the council's stance on gay rights issues shot an employee there before being restrained. Perkins is accustomed to controversy in the name of conservative causes.

As Perkins sees it, "there will be collateral damage to other freedoms" if gay marriage becomes more common. He cites recent cases involving parents who don't want their children to learn about same-sex marriage in school and photographers who don't want to work at same-sex weddings.

Like Perkins, Nance graduated from Liberty University, an evangelical Christian school in Lynchburg, Va., and has roots in religious conservatism. Like him, she bemoans federal data showing 42 percent of children are born to unmarried women.

And like single parents, gay couples offer only one side of the gender equation, she said.

"If this new union is to be treated in the same way as marriage, ignoring what the social data says, then you must teach it in the same manner in schools," Nance said. "And to say that children do not need a mother and a father is simply a lie."

Despite her beliefs, Nance -- like all the other opponents -- has gay friends and family. "We feel for them, and we care deeply about their well-being," she said, yet she worries that government acceptance will boost their numbers.

"When the law rewards something through licensing or benefits, there is always increased activity," Nance says. "We see this with marijuana in California, or gambling, prostitution, abortion or any vice that is legalized. Government endorsement lures people who would abstain otherwise."

Brown: 'The People are Definitely on Our Side'

The group responsible for coordinating these and other opponents is the National Organization for Marriage, led originally by Gallagher and now by Brown.

Compared with the gay rights movement, the group is dwarfed. It spent just $150,000 lobbying in the past two years, according to the nonpartisan Center for Responsive Politics, compared with $3 million by the Human Rights Campaign and $650,000 by the group Freedom to Marry.

Even so, Brown notes, opponents helped to pass laws and voter initiatives against gay marriage in 38 states. Nine states and the District of Columbia allow same-sex marriage -- including three states where voters approved it last fall.

"The people are definitely on our side," Brown says. "The fight is not over. We have not lost the Supreme Court."

Since the Family Research Council shooting, Brown's organization has hired an armed guard in its Washington office, and hecklers are a common problem. Brown, however, says he's not intimidated.

He says he's been influenced by preachers of equality such as Martin Luther King Jr. and believes in "the profound worth of every human being." But he's had trouble maintaining past friendships with gays who don't agree with his position on the issue.

"It's definitely put a strain on the relationships," he said. "Those friendships are not the same as they were before."

Gallagher came to the issue from an unusual starting point -- as a single mother of a child born out of wedlock.

"I didn't really see why you had to be married," she says of her college years and early adulthood. What she found was that "it's extremely difficult to be an unwed mother, which is not news now."

Like Brown, she remains optimistic about banning gay marriage in the states and the courts. But even in defeat, she says, the opposition will grow stronger, much like the abortion opposition after the Supreme Court's 1973 ruling that legalized abortion.

"I don't believe in inevitability," Gallagher said. "We make the future happen, and we're in the process of making a decision."

Richard Wolf writes for USA Today.

c. 2013 Religion News Service. Used with permission.

Publication date: March 26, 2013