It’s a bright, sparkling Sunday afternoon in Los Angeles, and about a thousand people of all hues and ages are flocking to the south lawn of City Hall. The majority of the crowd is Chinese, but there’s a sizable group of Latinos and pockets of South Asians, Koreans, Vietnamese and Indonesians. There are only a handful of black people, but they flow with ease through the throng. There are a few conspicuous white guys in suits too, cloistered around the stage where a band plays sing-along tunes. The mood is buoyant, affectionate. There are balloons and banners everywhere; a jolly Chinese mother cuts up a cake; snapshots are taken; cars honk. People gather in family clusters; grandparents play with children–who make up about half the crowd.

It’s the happiest, most diverse political event I’ve ever been to, and it’s not for Barack Obama. It’s for Proposition 8–the California ballot initiative that would eliminate the right of gays and lesbian to marry, which some 14,000 same-sex couples have exercised since the state Supreme Court ruled in their favor earlier this summer. Here and now at City Hall, where a good share of those same-sex weddings took place, there’s not a single Obama or McCain button in the mix. Instead, everyone is wearing red t-shirts that proclaim in both English and Chinese–Protect Marriage. Yes on 8. The toddlers’ shirts have an added touch: I Love My Mommy and Daddy.

When I ask people whom they’ll vote for, a few say McCain; a few more say Obama. But the vast majority say, "Yes on 8."

But who will you vote for? You know, like, for President?

"Yes! Yes on 8!"

It’s a mantra repeated like a drum beat all afternoon, and if there’s a scary, drone-like quality to the response, it’s by no means unique to this rainbow coalition of heterosexual marriage activists. With California in the bag for Obama and without a gubernatorial or Senate seat at stake, Prop 8 is the top of the ballot here, especially for the state’s right-wing, which has staked its power, prestige and, apparently, its hope for the future of America, on the outcome. As one of the apocalyptic slogans for "The Call"–a 10,000-strong prayer vigil and fast of white evangelicals on Saturday at San Diego’s Qualcomm Stadium–put it, "As California goes, so goes the nation."

Right now, polls show the measure as a toss-up. The money is dead even too. When all is said and done, both sides will have raised more than $35 million each–more than $70 million in all–making it the second most expensive race of 2008, second only to the presidency. A sizable minority of this money has come from out of state: from gay activists, celebrities and business leaders on the No side; and from the holy alliance of Mormons, Catholics (the Knights of Columbus) and Christian evangelicals (Focus on the Family, American Family Association, Concerned Women for America and Elsa Prince, mother of Blackwater founder Erik Prince) for the Yes team. As California goes, so goes the nation.

But the money is only part of the picture. What this money has enabled–for both sides–could spell lasting changes in California’s political landscape, and perhaps for the country as a whole. For the gay movement, Prop 8 marks the first time since the 1978 Briggs Initiative (more than a full generation ago) that they’ve had to run a real statewide, grassroots campaign. Prior victories for marriage equality came legislatively (through lobbying) or through litigation, and the lack of organizing chops showed in the early stages when they were simply out-fundraised, out-manned and out-hustled by the Protect Marriage crowd. But when polls suddenly showed Prop 8 forces in the lead early this fall, previously apathetic gays and lesbians suddenly came alive.

Almost every gay person I speak with sees the measure as an act of hateful discrimination for which the term homophobia is inadequate and thus rarely invoked. Instead, they use words like "apartheid" and "Jim Crow." The multi-faith No on 8 speakout I went to on Saturday began with an invocation of the Holocaust poem "First They Came For…" The ubiquitous No on 8 TV ads (countered minute-for-minute with Yes on 8 commercials) place Prop 8 alongside Japanese internment, redlining and anti-miscegenation laws as shameful episodes of American history.

If some of these analogies are a stretch–nobody is proposing queer concentration camps–the sense that one is being made a target, an object of revulsion, contempt and ridicule is palpable. This shared sense of vulnerability–and the deep well of empathy it elicits from straight allies–has been a powerfully galvanizing force for gay activists. If they win, if they defeat Prop 8, it will be because they were able to frame marriage discrimination against them, a small minority, as a salient issue for the majority. In doing so, they will have disproved the conventional wisdom that support for marriage equality must rely on "activist judges" and cannot be accomplished through more directly democratic means. If Prop 8 goes down, California will have twice approved same-sex marriage in the legislature, once in the highest court and at the polls.

This is no small feat. In fact, it has never been accomplished before. In Arizona, the only other state to vote down an anti-gay marriage initiative in 2006, concern that the overly broad measure would take away rights for unmarried straights proved the tipping point. The California measure is much more narrowly drawn. Indeed, for all the expense, there are almost no rights beyond marriage itself at stake for California queers much less anyone else. That’s because the state’s domestic partnership law already provides all the partnership rights a state can give absent federal marriage laws (a point that pro-Prop 8 spokesmen trumpet and that anti-Prop 8 forces discuss with reluctance). Most legal experts agree that even the thousands of hurry-up nuptials performed since June would not be invalidated should Prop 8 prevail.

So what is at stake? A lot. First, there is the simple matter of simply debunking the manipulative lies told by the Yes on 8 campaign. Days before I arrived in California, they circulated a flyer to black households depicting a smiling Barack Obama saying "I’m not in favor of gay marriage…" The implication was that Obama has endorsed Prop 8; he has done the opposite. Then there are the other lies that tap into the entrenched notion that homosexuality is somehow a threat to families, to heterosexuality, to children and to "religious freedom." These constitute the right-wing’s main talking points: without Prop 8 first graders would be forced to attend lesbian weddings, churches would be required to perform same-sex marriages and those that refused would be stripped of their tax-exempt status. Speaker after speaker at the City Hall rally hammered home these fallacies to wild applause, but each has been debunked.

Behind the scrim of "religious persecution" (another phrase Yes on 8 folks like to use), however, lies theocratic monopoly power. Every faith can decide on its own whether or not to conduct same-sex marriages, and in a secular democracy, civil marriage would accommodate the broad spectrum of beliefs, but not require any one in particular. This is not what Mormon, Catholic and evangelical Yes on 8 advocates want. Like on the matter of abortion, it’s their own brand of religion they wish to enforce upon the state and the people.

Finally, there is the matter of religiously-inspired homophobia itself. Oddly, this is somewhat difficult to get at because Yes on 8 people rarely mention homosexuality (their campaign protects and celebrates heterosexuality; "we made the right choice" is another one of their slogans), and when they do it is in the language of love–love of family, the love between one man and one woman, love of children, and yes, when pushed love of the sinner.

As the City Hall rally comes to a close, a couple hundred gay activists have marched over from Pershing Square, and there’s a standoff on the corner of Spring and 1st Street. Cops are nervously keeping the factions on opposite corners, and the mood is tense. Wendy, a Chinese Yes on 8 activist I talked to earlier, grabs the bullhorn and screams to the gays across the corner: "We love you! First, we are here because we love you. We love you so much!"

Behind her lies a 12-foot banner that reads: Homosexuals and Lesbians are Anti-Species. I ask Wendy later what species are gays against?

"The human species, of course!" she says.