In an interview on the science in science fiction, novelist William Gibson noted, “[T]he future is already here. It's just not evenly distributed yet.” What Gibson meant was that the innovations in science fiction could already be found—at least in embryonic form—in our current ideas or technology. Much the same could be said about future social and legal norms concerning the institution of marriage—they are already here, they’re just not evenly distributed yet.

A prime example is the social and legal acceptance of polygamous marriage. The legal bulwark against polygamy was the first to go, dismantled by the Supreme Court ruling Lawrence v. Texas. “Liberty presumes an autonomy of self,” claimed Justice Anthony Kennedy in the majority opinion, “that includes freedom of thought, belief, expression, and certain intimate conduct.”

As Justice Antonin Scalia recognized in the minority opinion, the decision could be used to legalize bigamy and would be a “massive disruption of the current social order.” Last week Justice Scalia’s prophetic powers were confirmed, when a federal judge used the Lawrence decision as the basis for striking down part of Utah’s law against polygamy.

The latest ruling isn’t particularly surprising, of course. One man’s slippery slope is another’s ladder of progress. Homosexual activists needed over 30 years to go from the Stonewall riots, which marked the start of the gay rights movement, to Goodridge, the case that legalized same-sex marriage in Massachusetts. But they have paved a clearer path for polygamists. And, unlike gay marriage, polygamy already has a long-standing cultural precedent. All of the major world religions—Judaism, Islam, Hinduism, Buddhism and Christianity—have at one time in their history condoned the practice of taking multiple spouses.

The same holds true for most every culture on earth. Out of 1,170 societies recorded in Murdock's Ethnographic Atlas, polygyny (the practice of men having more than one wife) is prevalent in 850. Even our own culture, which has an astoundingly high divorce and remarriage rate, practices a form of “serial polygamy.”

Advocates for same-sex marriage often refer to polls showing the social acceptance of homosexual relationships as a justification for expanding the definition of marriage. From this we can adduce, a fortiori, that since polygamy has an even stronger claim to historical and cultural acceptance, it should be included in the new expansion of marriage “rights.”

The appeal to “rights” also undercuts any reason to give special preference to same-sex relationships over polygamous ones. The precedents established in Lawrence and Goodridge are equally applicable to polyamorous relationships and homosexual couplings. As Justice Scalia noted in his dissent in Lawrence, as long as polygamists are not violating established laws or committing child abuse, states no longer have the authority to regulate their living arrangements.

With this decriminalization comes the inevitable push for acceptance. It happened with homosexual relationships and it will happen with polyamorous ones, too. And why should society deny a man the right to marry all the women he loves? What reasons do those who favor gay marriage have for excluding polygamy? Having rejected all arguments from nature and reason when they were used against their position, what do they have left to justify their discrimination?

The answer is nothing but arbitrary personal preference. Those who truly believe that homosexuals have a legal right to marry someone of the same gender have undercut the grounds for barring polyamorous groups from doing the same. If a man can marry another man why should he be barred from marrying two or three or four men if he chooses?

Unfortunately, many advocates of same-sex marriage are coming to the same realization, and instead of reconsidering their position, they merely shrug. They agree that allowing one requires allowing the other. But for them, polygamy is at worst an unfortunate but necessary tradeoff on the path to normalizing same-sex unions.

As usual, the progressive legal scholars are ahead of the curve. Six years ago Jonathan Turley, a law professor at George Washington University, made an eloquent case for the legalization of polygamy:

When the high court struck down anti-sodomy laws in Lawrence vs. Texas, we ended decades of the use of criminal laws to persecute gays. However, this recent change was brought about in part by the greater acceptance of gay men and lesbians into society, including openly gay politicians and popular TV characters.

Such a day of social acceptance will never come for polygamists. It is unlikely that any network is going to air The Polygamist Eye for the Monogamist Guy or add a polygamist twist to Everybody Loves Raymond. No matter. The rights of polygamists should not be based on popularity, but principle.

Turley was far too morose in his assessment. It took less than a decade for Kody Brown—the polygamist plaintiff of the recent Utah case who was represented in court by Turley—to get a reality TV show. In late 2010, TLC premiered “Sister Wives,” featuring Kody, his four “wives” (he’s legally married to only one woman), and their 17 children. The promotional material on TLC’s website invites us to “Follow the Brown family and see how they attempt to navigate life as a ‘normal’ family in a society that shuns their polygamist lifestyle.”

After watching several episodes from the first four seasons of the series I can testify that the Brown family is rather “normal”—at least by the standards of our 21st century “anything goes” culture. Sure, they’re a bit weird. But who isn’t nowadays? And by society’s moral logic, if you get to know someone and they seem nice and normal then you can’t condemn their lifestyle choices. As long as their flagpole is attached to a well-kept cottage, why shouldn’t they be able to let their freak flag fly?

Our fellow Christians are already leading the apathetic shrug in the name of “tolerance.” As one woman wrote on the TLC website:

First off I am not a Mormon, I am Baptist, and let me tell you, those who judge these people remember you shall be judged as you judge. This family is happy, these women all agreed to the arrangement. It is no different than a man having 4 mistresses and children by them. This way they all know about one another, there is no lying, no cheating, there is acceptance and an abundance of love. They need to be left alone to raise their children. God Bless the Browns and keep them safe.

That just about says it all, doesn’t it?

The social acceptance of polygamy is already here; it’s just not evenly distributed throughout society. At least not yet.