Benjamin E. Park is Associate Professor of History at Sam Houston State University. His books, Kingdom of Nauvoo: The Rise and Fall of a Religious Empire on the American Frontier and American Zion, provide a comprehensive view of Mormonism from the first revelations of Joseph Smith through the presidential ambitions of Mitt Romney. Together, they provide an introductory course in an American original.

Of all the novel American social-sexual arrangements in the antebellum years, from the strenuous celibacy of the Shakers to the untethered free love of Berlin Heights, perhaps no experiment has proven so durable to fame as Joseph Smith’s venture into plural marriage. A radical innovation that came to define the Latter-Day Saints and to delay Utah statehood for a period of decades, Mormon polygamy began as yet another accord between Smith and God, a secret covenant that granted the prophet rights to do things that he had wanted to do anyway, and at the very moment it first seemed plausible to do them without consequence. In both his Kingdom of Nauvoo and his more recent American Zion, Benjamin Park does an admirable job of recounting these events with candor, somehow threading a narrative needle between credulity and cynicism.

Though American Zion is the obvious choice for readers in need of a sweeping Mormon history, Kingdom of Nauvoo is the more granular and—in my view—more captivating take. Probably most readers don’t know that much about the saga of Nauvoo, so practically every page is a revelation. And yet I keep returning to one detail in particular, a representative anecdote that captures Smith’s psychology, his brazenness, and the remarkable influence he must have wielded over those in his orbit. It explains how he was able to generalize plural marriage, moving it beyond the confines of his own private practice and making the case for its adoption by others in the community.

That story centers upon Sarah Ann Whitney, one of more than two dozen women Smith married in secret before his first wife, Emma, found out. Whitney was 17-years-old in July of 1842; Smith was 36. By accounts an exceptionally attractive girl, she was also the daughter of prominent Mormon parents. When Smith approached Newel Whitney to ask for his daughter’s hand, he came with a written proclamation—written, that is, in the voice of God—promising an eternity of honor and immortality to the entire Whitney household once the couple was sealed.  Whatever reservations they may have felt about gifting their daughter to an already—in fact, many times over—married man, the offer was too good to refuse.

But though the marriage itself raises a host of questions and red flags, the situation became much more interesting the following spring, when Smith was confronted by a seemingly foreseeable problem. Sarah Ann Whitney was, in the eyes of Nauvoo’s young gentlemen, a very eligible bachelorette. No one knew that she was married to Smith, so she had both many callers to reject and no obvious reason to reject them all. Smith realized quickly that he needed a way to remove her from the dating pool without drawing any unwelcome attention to himself. He found that way in the sympathetic figure of a grieving widower, Sarah Ann’s uncle-by-marriage, Joseph Kingsbury.

Caroline Whitney Kingsbury had died the previous October, leaving her husband alone to raise their infant child. He was still very much in mourning when Smith came to him with a novel proposal. If Kingsbury would agree to be joined to Whitney in a “civil union”—not actually a marriage but something that looked to the residents of Nauvoo exactly like one—then Smith would seal him to his beloved Caroline for all eternity. When Kingsbury agreed to the scheme, he helped inaugurate a theological advance. If men and women could be united in civil bonds til death do they part, they might also be united spiritually in ways that death could not break, and this process might be formalized whether the spouse was living or dead.

Before long, a growing number of Mormon men were pursuing eternal seals with their lost wives, even in cases where they had already remarried and established such seals with their new brides as well. Though one wife was living and one (or more) dead, the man who secured these seals could already consider himself to have multiple wives, in a spiritual if not a physical sense. Looking ahead to the endless span of eternity, when all would be joined together forevermore, the matter of whether one or two or none of these wives were dead on earth seemed to matter less and less. Introduced and expanded gradually, starting with those—like the prophet’s moralistic brother Hyrum—who had loved and lost, it helped make polygamy palatable to many who might otherwise have rejected it out of hand. And it took off from there.

Polygamy was still noxious to just about everyone else, though, and the already swirling rumors help explain why the Mormons were run out of New York and then Ohio and then Missouri before Joseph and Hyrum Smith were lynched in Illinois, and why Brigham Young then bade America adieu entirely and started his people on the long western march to the Great Salt Lake, where polygamy persisted for most—but not all—of the rest of the century. From one vantage, the doctrine of plural marriage appears little more than a patriarchal swindle that permitted prominent men to have sex with several—even dozens—of women without violating social-religious standards of propriety or compromising their status as pillars of the community. Considered more generously, it was a complex social arrangement that empowered the prophet to bind his people tightly together in a cohesive matrix of interlocking and overlapping relations that would persist into infinity. My own judgment leans decidedly closer to the first of these interpretations. But the intricacy of the thing makes you wonder.

Ellen Wayland-Smith is Professor of Writing at the University of Southern California. Her book, Oneida: From Free Love Utopia to the Well-Set Table, documents the strange evolution of John Humphrey Noyes’ religious sect, from a collection of avowed Christian communists practicing “complex marriage” in the nineteenth century to a straight-laced, middle-class silverware company in the twentieth.

If Joseph Smith was perhaps the most audacious of the 19^th century’s religious-political-sexual innovators, he did not run unopposed. The perfectionist minister and self-proclaimed prophet John Humphrey Noyes also warrants consideration, and his contemporaneous Oneida Community rivals Nauvoo in a number of significant ways. Ellen Wayland-Smith’s Oneida: From Free Love Utopia to the Well-Set Table offers the most recent—and most comprehensive—account. Though the Latter-Day Saints appear here only in passing, the parallels between the Mormons and Wayland-Smith’s Oneidans are uncanny.

Like Smith, for example, Noyes declared a direct connection to God that justified both his critique of the prevalent social norms and his exploration of alternative arrangements. Also like Smith, Noyes’ revelations authorized him to have sex with lots and lots of women without forfeiting his claim to decency. And here again, Noyes founded his enterprise upon an apparatus of high-toned theological concepts that persuaded a bunch of perfectly respectable people to join in. If you end up thinking that Noyes did all this mostly just for the sex—as I mostly do—you still have to grapple with the complex theological reasoning that he used to validate his behavior.

Here’s the background: Starting in the 1830s, when upstate New York and New England were still much in the throes of the Second Great Awakening and its attendant millennialism, the young minister Noyes came to believe himself a special representative of God on Earth. (In this, he was not so dissimilar to Charles Grandison Finney, William Miller, or Lyman Beecher, to say nothing of Joseph Smith. If not in the water, special election seems to have been in the air.) Like many of the reformer class, Noyes condemned a pronounced selfishness in American society and sought means to correct it. He did so at the level of the family, through which individuals claimed ownership of their partners and children, and from which they laid claim to other people, properties, and assets. If this impulse were to be overcome, Noyes argued, Christians needed to become communists.

The Christian communism Noyes envisioned was realized finally in the 1840s and founded upon an institution that he called “complex marriage,” an arrangement by which all exclusivity was dissolved and every man in the community was in a sense married to every woman, and might therefore enjoy the conjugal benefits of each and all. No individual person could stake a claim on the life of any other, nor entertain feelings of jealousy in any justifiable way. To prevent rampant pregnancies, the men in the community practiced “male continence,” stopping somewhat short of full consummation. When babies were born, they were raised by the community in communal settings, denying parents any exclusive claim to their children. If any particular couple wished to have a child together, they had to apply to the community leadership for approval, which was granted or not based on the spiritual quality of the child that the couple seemed likely to produce. Sometimes those applications were approved. Otherwise, pairings were assigned. In either case, Noyes pioneered a form of spiritual eugenics not entirely dissimilar to the physical variety that would arise in the early 20^th century.

By 1845, when the new reforms were up and running and his Oneida community first beginning to flourish, Noyes had developed a theory of sexuality that drew on the early science of electricity, culminating in a theory of “electric sex.” The gist is that human beings are endowed with a life force traceable to Christ himself, and that this force can be transferred from person to person, growing in intensity with each transmission. A community of Christians bound by diverse connections would thus function as a spiritual battery, generating and containing enough electric potential to nurture health, ward off disease, and raise its members ever closer to true immortality. This sort of spiritual-physical growth took priority at Oneida, set against the compulsive, selfish, money-making obsession of the outside world. That was the appeal.

Unsurprisingly, though, Noyes’ sexual theory and practice found their way eventually into some extremely creepy places. Most disturbingly, Noyes took it upon himself to initiate all of the community’s girls into sexual experience immediately upon completion of puberty, around the average age of thirteen. There is also evidence that Noyes hoped to begin approving brother-sister sexual unions, and eventually to father a child with his own daughter. “Avuncular unions,” between uncles and nieces were already commonplace at Oneida. Eventually, the in-bred condition of the community would inspire Edgar Allen Poe’s story “The Fall of the House of Usher.”

By the end of the 1870s, the Oneida Community had collapsed under the weight of Mormon-inspired anti-bigamy legislation and Noyes had expatriated to Canada. Thus began the second life of the community, in which a group of avowed communist non-conformists began a transition to perfectly normal, bourgeois respectability by dropping the weird sexuality and leaning instead into the production of fine and affordable silverware.

Ultimately, both the Mormons and Oneidans buckled under political pressure and abandoned key elements of their belief systems. In hindsight, though, those key elements look a lot like the lecherous predilections of their all-too-human god-complex founders. That’s not to say that their social critiques were entirely wrong, or that middle class normalcy is necessarily right. But these parallel trajectories remain engrossing in themselves. They disclose a foundational libido at the base of very high-minded systems.