Some 15,000 fundamentalists are "independents" who aren't tied to any larger group or leader. They include headline grabbers like Tom Green and the late John Singer. Some independents, Wilde says, are still active LDS Church members "who remain quiet about their fundamentalist beliefs."

Her numbers and description jibe with information provided by the Utah Attorney General's Office, which tracks polygamous groups.

Beliefs go beyond marriage

At their core, Wilde says, is a set of beliefs that goes beyond plural marriage. In fact, when a potential fundamentalist comes to her living room in Cottonwood Heights to chat, she says it's always a red flag if the first question is "how can I find a second wife?"

"Until you have a testimony of some of the other basic principles of the gospel," she tells these men, "you're at the wrong end of the ladder." Polygamy, she says, has to be lived "righteously." It is difficult, she says, "to live it on a spiritual plane."

It's also difficult to define what "righteously" means to so many different leaders and sects, but Jeffs is learning the definition of what is legal under civil law. While his lifestyle is technically illegal in Utah, Jeffs was only hunted down after allegations that he facilitated illegal sexual relationships between young girls and older men. He was charged in St. George on Wednesday with two counts of rape as an accomplice, a first-degree felony.

While such crimes make polygamous groups a magnet for publicity, multiple wives and dozens of children are simply the most visible component of an inner faith commitment driving the movement. Fundamentalists believe that plural marriage is the literal key to the highest heaven in the afterlife. Many expect an everlasting reward based not only on the number of wives and children they have (the more the better), but for enduring persecution of their faith.

The "media serves prurient interest" by "choosing to portray (fundamentalism) in a particular way because it's good press," says University of Utah historian Martha Sonntag Bradley, who has researched and written extensively on polygamy. She said the study of religious doctrine and the FLDS vision of heaven "is much less interesting, but it's absolutely at the core" of why polygamists live as they do.