For most Mormons, the last few weeks have been a time of shocks. Gordon B. Hinckley, the president and prophet of the Church of Jesus Christ of Latter-day Saints, as the faith is formally known, died Jan. 27 at the age of 97.
Then Mitt Romney, the former governor of Massachusetts, last week suspended his campaign for the presidency; he was the first Mormon with a plausible chance of winning a major party's nomination since his father, George Romney, ran in 1968.
Mr. Romney's setback surely must have demoralized Mormonism's foot soldiers. They are the young men in black suits, white shirts and ties who pass out church literature on street corners in cities around the world, including New York City.
But that does not seem to be the case, if Siale Langi, 20, and James Kelley, 19, two Mormon missionaries in Manhattan, are any indication.
True, Mormonism has always had a reputation for unshakable optimism whatever the setbacks of the day. But missionaries are also unusually blinkered, forbidden from reading newspapers, watching television or listening to the radio.
As of 1:30 p.m. on Saturday, nearly 50 hours after news broke of Mr. Romney's withdrawal, Mr. Langi and Mr. Kelley had still not heard of it, nor were they told.
Asked if anything had surprised him in current events, Mr. Langi replied that some New Yorkers had mentioned a public-television series on the Mormons that was broadcast last year. Anything else? Yes, he continued, a 2006 film on a controversial chapter in 19th-century Mormon history called "September Dawn."
Mr. Kelley offered, "Some people have asked me, 'Are you hoping Mitt Romney wins?' I just say, 'Whatever happens is whatever happens.' "
Like other missionaries, who number about 170 in Manhattan, the Bronx, Westchester County and Connecticut, Mr. Kelley and Mr. Langi are carefully schooled to be politically neutral, said Richard Searle, mission president for the area. (There are about 73,000 Mormons in New York State.)
If people press missionaries on politics, Mr. Searle said, there are certain scripts. "We can tell you what Mr. Romney believes, if you would like to hear about the Gospel," Mr. Searle said, "but we don't have a position on him. We're not out campaigning, we're here to preach the Gospel."
A few hours spent on a chilly and rainy Saturday watching Mr. Langi and Mr. Kelley do missionary work showed two determined and amiable young men who are not easily distracted.
Walking in Chelsea past a red Lamborghini sports car parked in the street, two men in see-through T-shirts sharing a cup of coffee, and a large framed picture of Marilyn Monroe lifting barbells, Mr. Langi and Mr. Kelley looked only for the addresses of two possible converts who had said they wanted to hear a Mormon lesson plan. The people were not at home in either case.
On 14th Street, they returned to what they had done earlier in the day in Union Square: They approached dozens of people who walked quickly away and refused to make eye contact when they said, "Excuse me, have you ever heard of the Book of Mormon?"
The church values missionary work and accords missionaries the title of "elder," even though Mr. Langi and Mr. Kelly look even younger than their ages.
At 6-foot-2 and 280 pounds, Mr. Langi, a former high school football player who was born in El Paso, Tex., is an especially striking figure. The son of an Army medic and a bus driver, both of Tongan heritage, he can do the Haka, the Tongan war dance that involves stomping feet, bulging eyeballs and a protruding tongue.
Like Mr. Kelley, the son of an electrical engineer and a nurse, Mr. Langi saved up to $14,000 to finance two years of missionary work. (The church helps with finding apartments and other financial matters but does not finance the missions, which are voluntary.)
Mr. Langi has been in New York for nearly a year and a half and is teaching Mr. Kelley, a Salt Lake City native who arrived last month, the rigors of evangelizing. They live, with two other missionaries, in a modest two-bedroom apartment in Chinatown, Mr. Kelley in the top bunk bed and Mr. Langi in the bottom. The daily rigors and rhythms are not much different from when Mr. Romney was a missionary in France, in the late 1960s.
Mr. Langi has learned that those most likely to listen to church information are people "going through life changes," like having children or recently moving to town.
He is not above mentioning to sports fans that he has an uncle, Sione Pouha, who plays defensive tackle for the New York Jets.
Mr. Langi is also adept at occasional street debates when some contend that Mormonism has racist aspects. He just grins and looks down at his dark brown arms, in a theatrical gesture that seems to say, "I'm not exactly an albino."
Mr. Kelley is disarming in his own way. Pale and thin, he turns pink on a cold day like Saturday, his nose and ears turning crimson. Older women listen out of concern. Older men place a fatherly arm around his shoulder.
"It works for me," he said slyly.