They came in buses, from Utah and elsewhere, excited to help elect Mitt Romney in 2012. Spanish-speaking Mormon volunteers — former missionaries at ease making phone calls, knocking doors, and pitching strangers on the street — were a unique resource for the Republican nominee in the key southwest swing states.

In East Las Vegas, a Latino working-class neighborhood where the Romney campaign opened the first Republican office, around 10% of the volunteers were Spanish-speaking Mormons, according to former Romney aides. Outreach efforts in Colorado were similarly infused with bilingual Latter-day Saints. Romney's hardline immigration stance made the candidate a tough sell with Latino voters — but when the campaign ended, many in the party were hopeful that they'd tapped into a new longterm resource for the GOP.

Instead, four years later, Mitt's Mormon army is missing in action.

Not only is Donald Trump deeply disliked by Hispanic voters, according to polls; he is also historically unpopular with Mormons — struggling to consolidate support in deep-red Utah, and embroiled in a months-long feud with Romney, who's refused to endorse the nominee. That disconnect is depriving Trump — and his party — of free labor from one of the few GOP constituencies that could actually speak directly to Spanish-speakers.

Bettina Inclan, who led Hispanic outreach for the RNC before joining Romney as deputy coalitions director, said Mormon volunteers — many of them armed with experience as missionaries in Latin America — were indeed an important cog in 2012 Hispanic outreach.

"Having bilingual volunteers made it a lot easier to go into communities, to make the phone calls and do the outreach on the ground," said Inclan.

While other volunteers were intimidated by door-to-door canvassing, she said, the Mormon ex-proselytizers were unafraid, and comfortable striking up conversations with voters. "At the end of the day that’s what people want. People want to feel like their vote is important and that they're valued as individuals. That's why this outreach is so important."

Ryan Call, a Mormon who served as chairman of the Colorado Republican Party in 2012, said the party relied heavily on his coreligionists to reach Hispanic voters during the election. From his vantage point, he said, the Trump campaign is receiving a small fraction of that support.

"I think it's clear that they're having trouble drawing enthusiastic [Mormon] volunteers," Call said. "I can't tell you how many times I get cornered in the foyers at church and there's literal handwringing. They're concerned about whether they can even bring themselves to vote for Trump ... let alone volunteer for him, or be perceived as openly supporting him."

Call said it isn't just Mormons' language skills that made them valuable to Hispanic outreach efforts. He said he learned Spanish during his own Mormon mission in Southern California, and the experience altered his worldview.

"It very much colored my view on [immigration] issues," he said. "We do have a much more nuanced and kind of a personal perspective on the challenges of new immigrants," Call said, adding that many of the people he sought to convert as a young missionary were probably undocumented immigrants — "but we weren't asking them about their legal status; we wanted to share the gospel with them."

Josh Baca, who led coalitions for Romney in 2012, said in Colorado the top Spanish-speaking Mormon was Craig Romney, Mitt's son, who went on a bus tour that took him to intimate meet-and-greets in Colorado Springs and Denver with Hispanic leaders to try to dispel hardening perceptions of his father. Anyone can learn Spanish, Baca said, but Craig Romney "had a good appreciation for Hispanic family culture, he connected at a personal family level that made a big difference in regards to outreach to the community."

Jesus Marquez, a conservative Las Vegas radio host who knocked on doors for Jeb Bush in the 2016 primary, and is open to supporting Trump, said he hasn't seen the same commitment from Mormons in the state this time around.

"Not really, not here," he said. "The Mormons are not too involved, they were with Marco Rubio in the primary."

For now, many outreach-minded GOP operatives are already looking past 2016, hoping they'll be able to reignite the excitement among Mormon volunteers when they have a more palatable standard-bearer.

One Hispanic Romney staffer recalled entering the campaign's office in East Las Vegas — strategically situated near the city's Mormon temple — one day in 2012, and seeing it buzz with LDS volunteers.

"Fuck yeah, Mormons!" the staffer exclaimed to a colleague.

After being informed that the group might not appreciate such salty language, the staffer recalibrated: "Hooray for Mormons!"