What's the history of polygamy in North America?

In the 1800s, "Mormon" meant one thing: the Church of Jesus Christ of Latter Day Saints. In 1831, the head of the LDS -- the Prophet -- was Joseph Smith, and he believed God had ordered him to spread the practice of polygamy among his people.

Specifically, God revealed to Smith that Mormons were to practice polygany, which is the marriage of one man to multiple wives. (Polyandry is the marriage of one woman to multiple husbands, and polygamy is simply "plural marriage," which includes polygany, polyandry, and group marriages of multiple husbands and wives.)

The revelation was based on a simple principle: God wanted his people to multiply. Men can produce any number of offspring at one time, while women can only bear about one child per year. A marriage between a single man and multiple women would therefore bear a greater number of offspring than one between a single man and a single woman.

The Mormon Church refers back to God's directive in Genesis 1:28, "be fruitful, and multiply, and replenish the earth," for polygamy's ancient roots. Joseph Smith's revelation, the Divine Principle, is reflected in several passages of the Mormon scripture Doctrine and Covenants, including:

It's not all about multiplying, though. Smith and his followers also believed that plural marriage expanded the mind and the heart, encouraged patience, tested one's faith, and helped steer the righteous away from the sins of adultery and envy.

Still, in the aftermath of Smith's revelation, Mormons were faced with a difficult transition.

Polygamy was slow to spread throughout the Church, taking years to catch on. It was not an easy directive to accept. For one thing, plural marriage was, and still is, illegal all over North America; accepting Smith's revelation made Mormons outlaws (although the principle of religious freedom often protected them from government interference, at least in the beginning).

Plus, in a group of devout people who had always practiced monogamy, a directive for a man to have sex with more than one woman was a tough sell.

But within a couple of generations, Smith's example (he ultimately married dozens of women, some quite young) became, if not the norm, then at least pretty normal. Enough people engaged in polygamy that it became a core practice within the Mormon belief system.

That lasted for about 60 years. The Divine Principle is still in the Mormon scripture and is still respected by the LDS Church, but the practice is not. In 1889, then-President and Prophet Wilford Woodruff received a revelation stating that the time for polygamy (and the outlaw Mormon) had passed.

The next year, the LDS issued a decree that there would be no new plural marriages in the Church, and in the early 1900s, the Mormon leadership began to excommunicate those Mormons still forming new polygamous unions. Those excommunicated Mormons became the Fundamentalist sects that still engage in polygamy today.

This is an important distinction to make. The differences between LDS Mormons and Fundamentalist Mormons go beyond mere labels.

Misconceptions about the Mormon religion have become fairly ingrained in modern Western culture. Those who live far from mainstream Mormon communities often confuse Fundamental Mormonism with LDS Mormonism. This is a mistake.

Certainly, the most basic division between LDS Mormons and Fundamentalist Mormons is also the most obvious one: the practice of polygamy. In short, "Big Love" is not the mainstream.

LDS Mormons don't believe in plural marriage. It hasn't been sanctioned by the Church in well over 100 years. Fundamentalist Mormons do practice polygamy (although not every single one -- some believe in the Principle but choose monogamy for themselves). That is, at the core, what makes them "Fundamentalist."

But it's not the only thing. Aside from the plural-marriage issue, there are key lifestyle differences between LDS and Fundamentalist.

Mainstream Mormons are just that: mainstream. They may live in areas with large Mormon populations, but in much the same way as Muslims, Jews, Catholics, conservatives, liberals, or new immigrants may choose communities of like minds. LDS Mormons work, shop, dine and watch movies right alongside the rest of the general population. They tend to look just like any other conservatively dressed people out there.

And the LDS Prophet is not all-powerful; a council is involved in all Church decisions. That's a key difference: In Fundamentalist Mormon sects, the Prophet is entirely in charge. It's what can make Fundamentalist sects seem cultish to some. But it's important to note that the individual sects are just that: individual…

Not all Fundamentalist Mormon groups are alike -- there are anywhere from five to more than a dozen separate Fundamentalist sects out there, depending on how you define "separate," and each has its own Prophet, location, name and customs. While they all tend to live in tight communities, dress conservatively and practice polygamy, there are profound differences between them, too.

Many people have come to associate Mormon Fundamentalism with media images and information released after raids on polygamist compounds: child brides, women and girls who look like they stepped out of 1920s rural America, and fully isolated lives.

Many of those images are of the FLDS, or Fundamentalist Church of Latter Day Saints (which is not affiliated with the mainstream LDS Church). A lot of Fundamentalist Mormons in fact live more open, "normal" lives. They have ties to the community, dress conservatively but in today's styles, and have modern hair styles. They get married when they want to and they choose their own spouses.

In the end, of course, the practice of polygamy sets all Fundamentalist Mormons apart from the monogamous majority. In areas where they've settled en masse, though, polygamists tend to find a relatively laissez faire attitude on the part of government agencies and neighbors, their religious choice tolerated unless it impinges on other rights. A marriage involving three consenting adults, for instance, may skate by under "religious freedom." One between two consenting adults and a 14-year-old child would draw the cops if the truth got out.

But most Fundamentalist Mormons don't form marriages that include children. Most are, polygamy aside, law-abiding citizens who either contribute to the community or else live quietly outside it, and most of the monogamists surrounding them adopt a live and let live attitude.

Nonetheless, the division is deep: Most people don't marry two, three or 10 spouses, and the taboo seems to be an enduring one. As long as a Western marriage is between exactly two people, a certain degree of secrecy, and therefore separation, will be part of the polygamous lifestyle in North America.