Romney's political rise he is poised to become the first Mormon presidential nominee from a major political party excels that of other Latter-day Saints. But the hard knocks and homesickness, the mishaps and spiritual maturation that characterized his mission are shared by many in his church.
Today, some 57,000 Mormon missionaries march across the globe, proselytizing in public squares, knocking on doors and handing out religious tracts, often for nine or 10 hours a day, in fair weather and foul.
More than a million Mormons have served missions since Joseph Smith founded the church in 1830, LDS leaders say, volunteering for a duty once described as "a mix between monastic life, a fraternity pledge and pest-control salesmanship."
Most Mormon missionaries endure a grueling regimen of prayer, study and proselytizing. They put careers and college on hold and move to mission fields where rejection is the norm. Some have been beaten, mocked, caught in gang crossfire, even killed. Romney himself was in a serious car accident and roughed up by a team of soused rugby players.
And yet, many Mormons say their faith flourished during their missions.
"In a lot of ways serving a mission is like going through a refiner's fire," said Rob Skidmore, who recalls bicycling in 100-degree heat and dodging paintballs fired from passing cars during his mission in Las Vegas from 2004-2006. "It's an arduous process, but in the end all of the impurities have been burned out."
Many returned missionaries concede that their time was not very valuable for gaining converts, according to a survey of American Mormons released this year by the Pew Forum on Religion & Public Life. And separate studies suggest that many of those converts later leave the church.
Still, 90 percent of returned missionaries say their service strengthened their own faith, according to the Pew study. Eighty percent say it helped prepare them for career success.
"In a lot of ways, the missionaries' first converts are themselves," Stephen B. Allen, managing director of the LDS Church's Missionary Department. "And that's life changing."
Pew's study does not include ex-Mormons who quit the church during or after their mission. But fewer American Mormons stray from the fold than do evangelicals, Roman Catholics, mainline Protestants and Jews. That exodus often begins during the college-age years precisely when most Mormons start their missions.
Encouraging young Mormons to chase converts instead of fancy cars or college romances, scholars say, undoubtedly boosts the LDS Church's retention rate.
"There is a sense that missions serve a twofold purpose: to bring in converts, but also to make young people more devoted to the faith," said Matthew Bowman, author of The Mormon People, a recently released history of the church.
Mormons consider missionary work a priesthood duty, and all able-bodied and morally worthy men are encouraged to serve a two-year stint when they turn 19. Mormon women are eligible to serve for 18 months at age 21, but they cannot baptize converts, and just 11 percent become missionaries, according to the Pew study.
"It's not felt to be a responsibility of the young sisters to serve," Allen said.
If their application is accepted, the Mormons report to a Missionary Training Center most go to the one in Provo without any input about where they will serve. They contribute about $400 a month for living expenses, with many taking summer jobs and saving funds for years.
Described as "The Lord's Boot Camp," the MTC prepares Mormons for missionary life, enforcing a strict regimen that begins at 6 a.m. and leaves little time for anything but prayer, scripture study and language and cultural lessons.
The rules and regimen only intensify in the mission field.
A little white handbook instructs the missionaries never to leave their companion's side (except in the bathroom), not to call home except for Christmas and Mother's Day, and to refrain from secular music, books and other media. Dating much less embracing any member of the opposite sex in or near the mission field is grounds for dismissal.
Instead the missionaries don their formal proselytizing clothes the black name tags, dark suits and crisp white shirts and spend six days a week reading Mormon scriptures, praying or pounding the pavement for converts. Some also lead congregations and organize fellow missionaries.
"It's not like going on study-abroad program during college," said David Campbell, a political scientist at the University of Notre Dame who served an LDS mission in Illinois during the 1990s. "It's more like the military."
It can also be dangerous. Brian Carter, an attorney in Harrisburg, Pa., who served his Mormon mission in Ecuador from 1996-1998, said he was mugged and twice caught in gang crossfire.
"Coming from suburban California," he said, "I had never seen any of that."
But Carter and other Mormons say the skills and discipline they acquired in the mission field continue to enrich their faith and their careers.
Ann Norman has used the French she picked up during a Paris mission from 1996-1997 in jobs with the United Nations and consulting for several African nations.
Norman said public relations and fundraising she now oversees at Norman Communications an international firm with offices in Washington, New York, San Francisco and Sierra Leone are a cinch compared to converting the French.
"You are essentially selling the church as a missionary," Norman said. "And in France that's damn hard."
Norman said her 12 convert baptisms could be a record for her mission field, a feat that she intends to mention the next time she sees her friend and fellow Paris missionary, Mitt Romney.