WASHINGTON (RNS) -- They are moms and dads, authors and activists, a former police officer and a former single mom. They're black and white and Hispanic. One's a Roman Catholic archbishop, another an evangelical minister. Many have large families -- including gay members.

They are among the leading opponents of gay marriage, or as they prefer to be called, defenders of traditional marriage. And they're trying to stop an increasingly popular movement as it approaches two dates with history this week at the Supreme Court.

At times, it can seem a lonely battle. Outspent and lately out-hustled by highly organized gay rights organizations, opponents have struggled to get their story out. They're portrayed as bigots, likened to the racists and sexists of yesteryear. Some have been compared with hate groups like the Ku Klux Klan.

For men of the cloth such as Roman Catholic Archbishop Salvatore Cordileone, nothing could be further from the truth.

"Those who believe what every human society since the beginning of the human race has believed about marriage, and is clearly the case from nature itself, will be regarded, and treated, as the next class of bigots," he said. "That's untrue, and it's not kind, and it doesn't seem to lead to a 'live and let live' pluralism."

From his new post in San Francisco, a bastion of gay and lesbian activism, Cordileone chairs the U.S. Conference of Catholic Bishops' committee on the defense of marriage. He's one of the nation's leading opponents of gay marriage and is buttressed by a diverse crowd:

At the tip of the spear is the National Organization for Marriage, led by Brian Brown, a father of eight who travels the nation speaking at rallies opposing gay marriage. He succeeded Maggie Gallagher, a renowned conservative writer and speaker who warns about "losing American civilization."

The Family Research Council, headed by Tony Perkins, has been labeled a hate group by the Southern Poverty Law Center for "defaming gays and lesbians." Perkins, a father of five, authored the nation's first "covenant marriage" bill as a Louisiana state legislator in an effort to combat no-fault divorces.

One of the nation's leading female opponents is Penny Nance, president of Concerned Women for America, founded in 1979 by Beverly LaHaye. Fighting gay marriage is the hardest issue for the group because it's so "complicated and deeply personal," she said, but adds, "We believe that we must stand for truth no matter who it offends."

Leading a group of conservative black pastors is the Rev. William Owens of Memphis, Tenn., whose eight children range from age 50 to 4 months. For him, opposing same-sex marriage is part of the battle to rebuild African-American families after decades of absentee fathers. "We already have enough problems," he said.

New York state Sen. Ruben Diaz, one of the nation's most prominent Hispanic opponents of gay marriage, is used to tilting at windmills. An evangelical minister who has compared abortion with the Holocaust, he was the lone Senate Democrat to oppose the gay marriage law signed by Gov. Andrew Cuomo in 2011.

What ties this diverse group together is a belief that legalizing more same-sex marriages will harm the family, particularly children, while encouraging homosexuality and infringing on educational and religious liberty.

Their battle will culminate Tuesday (March 26) with a "March for Marriage" in the nation's capital, the same day the Supreme Court kicks off two days of oral arguments that could change the face of marriage in America. California's Proposition 8 ban on gay marriage will be addressed first in a case that could affect other states as well, followed by the federal Defense of Marriage Act's denial of government benefits to same-sex spouses.