More startling still was the abrupt about-face of the Rev. Rick Warren, the hugely popular megachurch leader whose endorsement last year of Proposition 8, California’s same-sex marriage ban, had roiled his appearance at the Obama inaugural. Warren also dropped in on Larry King to declare that he had “never” been and “never will be” an “anti-gay-marriage activist.” This was an unmistakable slap at the National Organization for Marriage, which lavished far more money on Proposition 8 than even James Dobson’s Focus on the Family.

The Obamas’ dog had longer legs on cable than the news from Iowa and Vermont. CNN’s weekly press critique, “Reliable Sources,” inquired why. The gay blogger John Aravosis suggested that many Americans are more worried about their mortgages than their neighbors’ private lives. Besides, Aravosis said, there are “only so many news stories you can do showing guys in tuxes.”

As the polls attest, the majority of Americans who support civil unions for gay couples has been steadily growing. Younger voters are fine with marriage. Generational changeover will seal the deal. Crunching all the numbers, the poll maven Nate Silver sees same-sex marriage achieving majority support “at some point in the 2010s.”

Iowa and Vermont were the tipping point because they struck down the right’s two major arguments against marriage equality. The unanimous ruling of the seven-member Iowa Supreme Court proved that the issue is not merely a bicoastal fad. The decision, written by Mark Cady, a Republican appointee, was particularly articulate in explaining that a state’s legalization of same-sex marriage has no effect on marriage as practiced by religions. “The only difference,” the judge wrote, is that “civil marriage will now take on a new meaning that reflects a more complete understanding of equal protection of the law.”

Image Frank Rich Credit... Fred R. Conrad/The New York Times

Some opponents grumbled anyway, reviving their perennial complaint, dating back to Brown v. Board of Education, about activist judges. But the judiciary has long played a leading role in sticking up for the civil rights of minorities so they’re not held hostage to a majority vote. Even if the judiciary-overreach argument had merit, it was still moot in Vermont, where the State Legislature, not a court, voted to make same-sex marriage legal and then voted to override the Republican governor’s veto.

As the case against equal rights for gay families gets harder and harder to argue on any nonreligious or legal grounds, no wonder so many conservatives are dropping the cause. And if Fox News and Rick Warren won’t lead the charge on same-sex marriage, who on the national stage will take their place? The only enthusiastic contenders seem to be Republicans contemplating presidential runs in 2012. As Rich Tafel, the former president of the gay Log Cabin Republicans, pointed out to me last week, what Iowa giveth to the Democrats, Iowa taketh away from his own party. As the first stop in the primary process, the Iowa caucuses provided a crucial boost to Barack Obama’s victorious and inclusive Democratic campaign in 2008. But on the G.O.P. side, the caucuses tilt toward the exclusionary hard right.