There’s nothing cooler in today’s overwhelmingly white, overwhelmingly Anglo Republican Party than being neither. For its State of the Union rebuttal, the GOP tapped Cuban-American Florida Sen. Marco Rubio. Rubio had already introduced Mitt Romney at the Republican National Convention, while Puerto Rican first lady Lucé Vela Fortuño introduced Romney’s wife, Ann. When a Senate seat opened up in South Carolina last December, party elders chose African-American Rep. Tim Scott. And Republicans have just founded a new organization to groom minorities in the party. The GOP will never rebound, explains the group’s chairman, African-American former Republican congressman J.C. Watts, “until you get people that look like me in the trenches.”

Republicans probably overestimate the traction they’ll get from changing the color and accents of their pitchmen. There’s something deeply patronizing about the GOP’s assumption that while its voters are motivated by ideology, Latino and black Democrats act merely on ethnic or racial affinity. The harsh truth is that the single biggest reason Latinos and African-Americans vote Democratic is that they mostly agree with Democrats that government should do more for people in need, even if that means less military spending and higher taxes. Even immigration drives Latino voting far less than many Republicans seem to believe.

But at least the GOP’s new cult of racial and ethnic diversity bespeaks some recognition of the way America has changed. Where the party remains in deep denial is on the question of sexual orientation. For the Republican Party to truly compete in 21st-century America, it’s going to need more than merely black and brown spokespeople. It’s going to need openly gay and lesbian ones, too.

When it comes to accepting lesbians and gays, today’s Republican Party lags decades behind the Democrats. In 1977, when Ed Koch first ran for mayor of New York, he publicly consorted with former beauty queen Bess Myerson to deflect rumors that he was gay. In today’s Democratic Party, such a charade would be almost unimaginable. The party boasts openly gay, lesbian, or bisexual members of Congress, and a lesbian Democrat leads the race to be the next mayor of New York. In today’s GOP, by contrast, not much has changed since 1977. Gays now serve openly in the Marine Corps, but being a gay or lesbian politician in the GOP still generally requires staying in the closet—at least until you’re outed in some humiliating scandal.

It’s easy to see why the GOP is not searching for openly gay and lesbian spokespeople in the same way it is hungering for black and Hispanic ones. Being a prominent African-American or Latino Republican may be tricky, but it doesn’t require embracing a party that explicitly opposes your right to get married, or to be free from various other forms of discrimination. And while some national Republican leaders now embrace a path to citizenship for illegal immigrants as a way to win over Hispanics, there’s much less interest in embracing gay marriage in order to win over lesbians and gays. To the contrary, GOP strategists sometimes suggest that Latinos and African-Americans can be wooed to the GOP precisely because they are “culturally conservative” on issues like gay rights. In other words, homophobia is part of the Republican Party’s outreach strategy.

But while it may sound plausible to use the GOP’s opposition to gay marriage to help build a coalition among whites, Hispanics, and blacks in the same way Ronald Reagan used cultural conservatism to help bring together white Southern Protestants and white Northern Catholics, there’s a problem. The problem is that the GOP’s problems are not just ethnic, they’re generational, too. Since younger Americans of virtually every ethnic and racial group are far more supportive of gay rights than are their elders, stitching together a multi-ethnic coalition against gay rights means building a coalition of the old. Even more important, for many younger Americans, supporting gay equality has become a symbol of modernity, as obvious and uncontroversial as knowing how to use Facebook. As Robert Draper noted in last Sunday’s New York Times Magazine, when male, 20-something Ohio swing voters were asked to describe the GOP, they volunteered words like “out of touch,” “hateful” and “1950s.” The party’s “brand,” one young Republican pollster told Draper, is “that we’re not in the 21st century.”

To overcome this generational disconnect, Republicans need to embrace gay marriage now rather than continuing to play catch-up as it becomes a fait accompli in more and more of the country. And they need to seek out gay and lesbian politicians who can personify the GOP’s new pro-gay rights stance. One useful role model is David Cameron, the Tory British prime minister who embraced gay marriage in 2011. Another is Chris Christie, who although he opposes gay marriage, last year appointed New Jersey’s first openly gay Supreme Court judge.

To embrace gay rights, Republicans don’t need to abandon cultural conservatism. To the contrary, an unthinking, bigoted opposition to gay equality is preventing Republicans from fashioning a more meaningful culturally conservative message for today’s age. The real threats to traditional values in America today don’t come from committed, monogamous gays and lesbians. They come from the breakdown of marriage among straight Americans, especially poor, straight Americans. For today’s GOP, seriously addressing the cultural and economic reasons that so many straight marriages fail is a better long-term political strategy than continuing to try to bar lesbians and gays from getting married in the first place.

Eventually, the Republican Party is likely to move in this direction, irrespective of the conflict it causes with the party’s Christian evangelical base. The sooner it does so, the faster it will make itself nationally competitive again.