I’ve always vowed I would never be one of those people–and you know who you are!–who cancel their ACLU membership in a fit of pique over a single issue. So I’ll just say that I was surprised to learn recently that the organization has a policy opposing laws against polygamy: “The ACLU believes that criminal and civil laws prohibiting or penalizing the practice of plural marriage violate constitutional protections of freedom of expression and association, freedom of religion, and privacy for personal relationships among consenting adults.” A footnote explains that “plural marriage” is a gender-neutral term.

Unfortunately, in the real world, it’s not. The ACLU policy was set back in 1991 in response to a child-custody case in Utah, where at least 25,000 fundamentalist Mormons still follow the path of Brigham Young, husband of twenty-seven, and where “plural marriage” means only one thing–polygyny, or one man with multiple wives.

Depending on whom you talk to, polygyny is either openly tolerated in Utah–until this year no one had been arrested for it in half a century–or severely stigmatized. Polygyny became a hot topic there last year, when a 16-year-old girl belonging to the secretive Kingston Order sought to leave her “marriage”–she was her uncle’s fifteenth “wife”–and was beaten unconscious by her father. After a major brouhaha–Republican Governor Mike Leavitt seemed surprised to learn that polygyny was illegal–the uncle was convicted of incest, and the father of child abuse. Polygyny itself was never at issue. The girl, who had been pulled out of school in the seventh grade, is now in protective custody, catching up on her education and being a teenager.

The girl’s story is not uncommon, says Carmen Thompson, a former polygynous wife who directs Tapestry of Polygamy (www.polygamy.org), an eighteen-month-old volunteer organization that assists women in flight from polygynous marriages. Tapestry has aided some 300 “refugees” just since the start of this year, and their stories are hair-raising: incest, abuse, children who have no birth certificates and are never sent to school, threats of “blood atonement” (death) made to fleeing wives. This reality recedes from view, though, when you put on libertarian glasses. Then the important testimony comes from Elizabeth Joseph, poster girl for “feminist polygamy.” As she put it in a New York Times Op-Ed, you get to have your career, a co-wife watches your kids, and the children have a strong paternal authority figure. A feminist touting the virtues of patriarchal dads makes me a bit suspicious, but in any case, Joseph, a lawyer and radio-station operator who isn’t a Mormon and who entered her “marriage” with one man and seven other women as a mature adult, is hardly a typical polygynous wife.

What’s wrong with legalizing polygyny? Consider the phrase “consenting adult.” After much Sturm und Drang, Utah raised the age of consent last year from 14 to 16–15 with the permission of a judge, who is barred by law from asking questions that might uncover coercion. Girls cannot refuse to be “home schooled,” and school authorities don’t insist that such schooling means math and history and English and science, with progress measured by tests. Instead, they look the other way when girls are pulled from school to work for free in clan businesses, as was the Kingston girl, while awaiting the summons to marry.

One Utah Civil Liberties Union board member said my arguments were “ethnocentric.” Leaving aside the appropriateness of the term, nobody would argue that cultural diversity is an absolute value overriding every other consideration. No one I spoke with at the ACLU had a problem with rejecting religious or cultural defenses of child abuse, domestic violence or female genital mutilation. “Violence is different,” ACLU director Ira Glasser told me. But if the ACLU is going to draw a line at all, why only there? Why not see polygyny as a human rights violation, a contract so radically inegalitarian–he has fifteen wives, each wife has one-fifteenth of a husband; she can have no more mates, he can have as many as he likes–that it ought to be illegal? That some women may find this arrangement acceptable doesn’t mean the law should permit it, any more than the law should let people work for a dollar an hour, or sell their kidneys, or clean houses off the books and wind up with no Social Security.

So what is the ACLU doing? Outside Utah, plural marriage is not an issue. But gay marriage is. Every person I spoke with connected the two issues, on the grounds that if you accept restrictions on the legal definition of marriage in the one case, you have no standing to argue against such restrictions in the other. “So if polygyny is the price of gay marriage, you’re willing to pay it?” I asked Glasser. Yes, he replied. But except for the fact that neither one is included in the legal definition of marriage, plural marriage and gay marriage have little in common. Two same-sexers are entering into the same contract as two heteros. That’s why people who argue gay marriage will “threaten marriage” can never say exactly what the threat is. But plural marriage is fundamentally different. It would redefine all marriage contracts, because every marriage would be legally open to the addition of more partners.

Of course, as Glasser and others were quick to point out, monogamous marriage is also often exploitative and harmful to women, and 15-year-old girls can be pushed into monogamous marriage too. Right! But those facts suggest that there’s something amiss with the whole strategy of trying to expand the marital population. Shouldn’t the real libertarian position be that marriage itself has to go? There’s something deeply contradictory about accepting the state’s right to privilege married people while denying it the right to decide who those people will be and to define what marriage is.

In a world where the age of consent was, say, 30, where teenage girls had real autonomy, where all women were well educated and able to support themselves and their children, and where people were less isolated and easily trapped, the libertarian position would make more sense. Polygyny, I suspect, would be a rarity–and maybe marriage too.