This is an archived article that was published on in 2013, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

While the Supreme Court ponders the constitutionality of the Defense of Marriage Act, activists along the political spectrum are voicing their opinions on monogamy's core institution and whom it should include. Most miss the following point: DOMA doesn't just prohibit gay marriage by defining marriage as the union of one man and one woman. It also prohibits plural marriage by limiting it to one and one.

The plural marriage movement is real. An estimated 50,000 to 150,000 polygamous families already live in America, from the well-publicized Muslims and Mormons to the African and Vietnamese immigrants keeping up their cultural ways. From modern feminists looking for a better work/life balance, to family traditionalists, who maintain that any marriage is better than none in the fight against the rising tide of single parents, cohabitation, and divorce.

Over 500,000 others identify as polyamorous, and engage in "ethical non-monogamy" — loving, committed, concurrent, consensual relationships with multiple partners.

The push for non-monogamous marriage reveals some unexpected bedfellows: Everyone from former presidents to the remarried elderly couple next door. Experts say that 30 to 60 percent of married people in the U.S. will commit adultery over the course of their 'exclusive, dyadic relationships,' producing a form of de facto polygamy. Thousands of others will actually marry a second, sometimes even a third person, albeit after a legal divorce from their original spouse.

The rise of no-fault divorce has made "polygamy on the installment plan" more and more common for adults of all ages. Whether it's de facto polygamy in the form of adultery, or serial polygamy with no-fault divorce, we as Americans have already broken the sanctity of the "couple."

While some believe that plural marriage could lead to harm against women, regulation would protect them. And what about egalitarian polygamy, based on adult consent? Is it inherently abusive? Or more abusive than many "traditional" marriages based on patriarchal domination?

If the concern were third-party harms against children, why would these kids be any different than the thousands who already grow up with more than two parents in their lives? Forget stepparents, open-adoptions, extended familial networks, and other "classic" multi-parental settings. In cases of egg donors and surrogate mothers, courts have ruled that children can have three natural parents. Maybe more is even better; recent studies indicate that children in polyamorous households benefit from increased attention and diversity of role models.

Those who would argue against plural marriage have their work cut out for them. The Bible records at least 40 instances of the practice. Confucianism, Islam, Hinduism, and some forms of Mormonism also support it. While Catholicism bans it, other forms of Christianity are somewhat less opposed.

Plural marriage is legal in more than 150 countries, with an estimated 2 billion practitioners and 3 billion supporters. Anthropologists believe that it was the norm through most of human history, until the sixth century Christian influence of the Roman Emperor Justinian. As a North American value, plural marriage is older than monogamy. According to one study of Native American tribes, a full 84 percent of them practiced it.

Natural law arguments also fail. Biologists lately have discovered that in the animal kingdom, there is almost no such thing as monogamy.

In 1878, the Supreme Court in Reynolds v. U.S. called plural marriage "odious," and an "offence against society." In Romer v. Evans (1996), and again in Lawrence v. Texas (2003), Justice Antonin Scalia's dissent warned against legalizing same-sex marriage, noting that once the court struck down a legislature's ability to uphold "morals-based legislation," the ban against plural marriage would be the next thing to go.

Since then, TV shows such as TLC's "Sister Wives," HBO's "Big Love" and Showtime's "Polyamory" have done much to sway public opinion in favor of poly-ness, bringing the concept into the nation's collective living room and consciousness.

With DOMA now on the table, it's time to bring the issue back to court.

Mark Goldfeder is an adjunct professor of law and religion at Georgia State University, and a member of the Center for the Study of Law and Religion at Emory University.