The Slippery Slope to Polygamy and Incest

AP Photo/Jonathan Ray Ward

Young girls outside a school in the polygamous commune of Bountiful, British Columbia

It’s been a few weeks since the victories in the marriage cases at the Supreme Court, and maybe it’s time for the political left to own up to something.

You know those opponents of marriage equality who said government approval of same-sex marriage might erode bans on polygamous and incestuous marriages? They’re right. As a matter of constitutional rationale, there is indeed a slippery slope between recognizing same-sex marriages and allowing marriages among more than two people and between consenting adults who are related. If we don’t want to go there, we need to come up with distinctions that we have not yet articulated well. 

The left is in this bind in part because our arguments for expanding the marriage right to same-sex couples have been so compelling. Marriage, we’ve said, is about defining one’s own family and consecrating a union based on love. We’ve voiced these arguments in constitutional terms, using claims arising from the doctrines of “fundamental rights” and equal protection. Fundamental-rights analysis says that marriage is for many a crucial element of human flourishing, or as the Court said almost fifty years ago “essential to the orderly pursuit of happiness.” Because it’s so important, government can restrict marriage only by showing a truly compelling justification. The equal protection argument is simply that the marriage right should not be taken away from groups unless the government has good reasons to exclude those groups. 

When it comes to marriage, the fundamental rights claims and the equal protection arguments often intertwine. For example, Justice Kennedy’s opinion last month striking down a portion of the Defense of Marriage Act said that DOMA’s injection of “inequality into the United States Code” violated the “liberty” protected by the Constitution. The “inequality” part is equal protection language; the “liberty” wording is fundamental rights stuff. The analytical box is not all that important. What it boils down to is that when the government wants to exclude groups from something important like marriage, it has to show good reasons for the exclusion. And prejudice—simply thinking something is “icky”—doesn’t count as a reason.

The arguments supporters of same-sex marriage have made in court do not sufficiently distinguish marriage for lesbians and gay men from other possible claimants to the marriage right. If marriage is about the ability to define one’s own family, what’s the argument against allowing brothers and sisters (or first cousins) to wed? If liberty protects, as Kennedy wrote ten years ago in Lawrence v. Texas, the case striking down Texas’s anti-sodomy law, the “right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life,” why can’t people in polyamorous relationships claim that right as well? If it’s wrong to exclude groups because of prejudice, are we sure the uneasiness most of us feel about those who love more than one, or love one of their own, shouldn't count as prejudice?

In private conversations with leaders in the marriage movement, I often hear two responses. The first is that there is no political energy behind a fight for incestuous or polygamous marriages. The second is that they would be fine if those restrictions fell as well but, in effect, “don’t quote me on that.” The first of these responses, of course, is a political response but not a legal one. The second is to concede the point, with hopes that they won't have to come out of the closet on the concession until more same-sex victories are won in political and legal arenas.

Can we do better? What are the possible distinctions?


This argument goes something like this: “Well, gay marriage is one thing. But incest and polygamy are icky.” I understand this visceral response. But of course this is the same kind of repulsion that has been standing in the way of LGBTQ rights for decades, and which motivated anti-miscegenation statutes before that. This kind of argument makes us sound dangerously close to those who oppose same-sex marriage by claiming it is “unnatural.” 

Think of the Children!

This argument is more relevant to incest than polygamy. Incest raises the risk of birth defects, or so we’ve been told. But the risks are reportedly small, and probably less than for parents over forty, or smokers, or those with certain hereditary diseases. If the government stepped in to regulate the decisions of potential parents on those grounds, we’d rightly dust off our “nanny state” bromides. This is the kind of thing we usually leave for people to decide for themselves. Here, too, the argument that marriage is about protecting the children sounds eerily familiar to the arguments trotted out against same-sex couples for years. And even if we wanted to intervene to protect the potential offspring of incestuous couples, there are things we could do (mandatory genetic counseling, for example) short of outright bans on their marriages.

Polygamy and Incest are Coercive.

Perhaps polygamous and incestuous bonds are more likely to be coercive, especially for the women involved. Polygamy is often used to bolster a misogynistic, male-dominated family structure; incest is frequently the product or symptom of abuse and subjugation. To the extent coercion is present, then polygamous and incestuous marriages do not result from the exercise of free will and genuine choice. 

This can be a strong argument, when borne out by facts. Father/daughter incest, for example, is surely so likely to be problematic on consent grounds that a government can ban it. But the further you get from that kind of genuine power imbalance, the weaker the coercion argument becomes. First cousins, it seems to me, are no more likely to be wrapped up in a coercive relationship than any other couple, related or not. (About twenty states, in fact, allow first cousins to marry—more than allow same sex couples.) And while polygamous marriages may more likely embody traditional stereotypes and roles, since when has that been a matter of government concern? As long as each individual who enters into a polyamorous relationship does so freely, and as long as divorce is available if they want out, then arguments from coercion are not particularly powerful.

Polygamy and Incest are Choices.

If the coercion argument doesn’t persuade, we could swing the other way and say sexual orientation is hard wired, but polygamy and incest are choices. In equal-protection analysis, the Court has suggested that discrimination based on immutable characteristics is more suspect, meaning the government has to show a more significant justification for the classification. 

But arguments from immutability are awkward in this context. Maybe I am speaking out of school here, but arguments for marriage equality do not really depend on the claim that people have no choice about who they are. Rather, the argument that resonates most with Americans is that LGBTQ people have the same right to make choices about their families as straight people. Let’s be honest: If science revealed tomorrow that sexual orientation is fluid and changeable, the arguments in favor of marriage equality would essentially be the same, wouldn’t they? Just like our arguments for religious liberty do not depend on whether people are destined by biology to be a Methodist, our arguments about the liberty to marry need not depend on science. In any event, if we throw all our eggs in the “it’s about the hardwiring” basket, are we sure we have made the distinction we want? Are we confident that science will show that people who are polyamorous or who are attracted to a cousin are not hardwired that way? 

LGBTQ Groups are Less Politically Powerful.

The conventional view of the equal protection clause is that it empowers courts to step in to protect—in the words of the leading Supreme Court case on point—“discrete and insular” groups that are systemically disadvantaged in the political process. So to make this argument, we’d have to say that gay-rights groups are less influential in mainstream politics than those who advocate for polyamory and consensual incest. That seems flat wrong. Political successes with regard to same-sex marriage are only recent, to be sure. But the political trend is clear, and marriage equality will be a reality for most same-sex couples in America in the foreseeable future. If anything, the argument from political disenfranchisement cuts the other way—that polygamous and incestuous couples deserve more constitutional protection than same-sex couples. 

If these distinctions do not hold water, we have two options. We can continue to search for differences that make sense as a matter of constitutional principle. Or we can fess up. We can admit our arguments in favor of marriage equality inexorably lead us to a broader battle in favor of allowing people to define their marriages, and their families, by their own lights.

You may also like