Bob Vander Plaats, fresh off a failed bid for Terrace Hill, had surprisingly positive momentum. After spearheading a successful campaign — along with his brand-new organization, the Family Leader — to recall three Supreme Court justices who had ruled in favor of same-sex marriage, he was on a fast track to become kingmaker in Iowa’s Republican caucuses.

But Vander Plaats bungled his transition into national politics. A Marriage Vow that was supposed to catapult him to the top of the GOP endorsement list drew nationwide controversy. A few weeks later, a video was released of Vander Plaats comfortably laughing at a homophobic joke.

With GOP candidates brushing off his pledge, Vander Plaats’s success is teetering. Maybe it’s a good sign — perhaps overt homophobia and far-right social prescriptivism are no longer easy ways to secure the GOP base.

On July 7, Vander Plaats made his triumphant announcement: To have a shot at his prized endorsement, candidates would have to sign on to the Family Leader’s Marriage Vow.

Rep Michele Bachmann, R-Minn., and former Sen. Rick Santorum, R-Pa., immediately signed the document, a two-page statement with dozens of footnotes that declared personal fidelity, opposition to "the redefinition of marriage," rejection of "Sharia Islam[sic]," and opposition to pornography and abortion. Shortly after, the national media noticed the first tenet: "A child born into slavery in 1860 was more likely to be raised by his mother and father in a two-parent household than was an African-American baby born after the election of the USA’s first African-American President."

The implication, of course: Black children were better off under slavery. Amid national mockery and denouncement, the Family Leader excised the section and released a public statement declaring that slavery was, of course, awful for families.

But the criticism had only begun. Former New Mexico Gov. Gary Johnson seized on the pledge as a wedge issue, announcing July 9 that it was "offensive to the principles of liberty and freedom on which this country was founded."

Other contenders refused to sign, as well: Herman Cain, Tim Pawlenty, and Mitt Romney declined, although none so ferociously as Johnson.

Even Vander Plaats’ former supporters and staffers have weighed in opposing him. Iowa House Speaker Pro Tem Jeff Kaufmann, R-Wilton, was Vander Plaats’ Cedar County chairman during his 2002 campaign. During the time of the pledge dustup, Kaufmann emailed Family Leader executives, including Vander Plaats, saying that the pledge had "ridiculous implications."

And then the video appeared on July 19: Vander Plaats in March. "You know what my wife says?" an off-camera man asks, then answers: "Iowa: Where you can’t smoke a fag but you can marry one."

Vander Plaats guffaws, leaning back in his chair; it takes him a few moments to regain composure. "Oh, shoot," he says, wiping his eyes. "That’s pretty good."

Thankfully, we’ve come far enough as a society to frown on fag jokes. Gay-rights organization One Iowa began a petition demanding Vander Plaats’ apology; he’s made no comment about the incident, although it’s drawn widespread negative attention.

There’s an irksome coastal smugness around the national criticism of Vander Plaats, as though he confirms the stereotype of the backwards Midwesterner. But if we put this aside, there’s something important about Vander Plaats’ falling star: This isn’t the 1980s, and there’s no Moral Majority rising out of the Family Leader. Efforts to stoke the fires of social conservatism the old-fashioned way, with an invocation of Christian family paragons, are failing.

Two months after Iowa State University political-science Professor Steffen Schmidt called him"remarkably and frighteningly successful," Kaufmann wrote to Vander Plaats to tell him that his "political credibility is waning."

Vander Plaats isn’t irrelevant, of course — at least not yet. But he’s learning that an anti-gay agenda makes a poor foundation for politics in a country that is becoming more tolerant.

And that — ignoring any potential schadenfreude — is worth celebrating.