The subtlety comes from a feeling that there is a "proper etiquette" in Utah, at least for statewide or congressional offices, when it comes to announcing one's religion, he says. "The vast majority of LDS voters would think it's inappropriate; it might be seen as a crass use of service to their church." And, too, "they've been sensitized by non-members' (of the LDS Church) feelings that the church is running things, whether overtly or not. So anything that reinforces that, especially in an in-your-face way, makes a lot of members nervous."

And if the race is for Salt Lake City mayor, being LDS might be a liability. It's been 24 years since an active Mormon was elected mayor of the city, and in this campaign season people have been wondering out loud whether a Mormon can ever win here, where 53 percent of the population is believed to be non-LDS.

The Web sites of Salt Lake's mayoral candidates include almost no church membership information: The closest thing you'll find is J.P. Hughes' bio, which includes the fact that he is the bishop of a University of Utah LDS student ward. Tucked into Keith Christensen's bio is the fact that he graduated from Brigham Young University.

But last month Christensen wrote an op-ed piece for the Deseret Morning News in which he corrected a previous newspaper story that said, "He used to be both Mormon and Republican. Now, he's neither." "(T)he Deseret Morning News was flat wrong in saying I wish to eschew myself of my faith," Christensen wrote. "Despite a mean-spirited whisper campaign by one opposing campaign, I am Mormon and am proud of my heritage."

That said, he went on, "I believe that religion should not play a role in the mayoral race nor in the mayor's office. In the darker recesses of human nature, there is a tendency toward an 'us vs. them' mentality."

The religious divide is alive and well in Salt Lake City, says City Council member Jill Remington Love. Mayoral candidate Dave Buhler, who is LDS, "time and time again has to say to people he might be asking support from, 'I know you're not going to generalize who I am because of my religion, and labels shouldn't matter.' ... I think Dave has his fingers crossed that Salt Lake residents will be big enough to judge him as an individual."

It's mostly pundits and opponents who focus on a candidate's religion, she says. "It's not something I've ever been asked by a voter."

City Council member Nancy Saxton says she has never brought up religion in her campaign, but occasionally voters in her very Democratic district have asked, "Are you one of those Mormons?" Saxton was raised Mormon, considers that background "very precious," married a Presbyterian and worships at Wasatch Presbyterian Church — a nuanced history she tries to succinctly explain if anyone asks.

In other parts of the United States, the relative importance of a candidate's religion varies from region to region, urban to rural. "In states that are more secular, that contain our biggest cities, party activists aren't necessarily looking as hard for the religious credentials," says Clemson's Olson.