The Emory Law Journal has a symposium on the constitution and polygamous marriage. Some articles are on whether the government may criminalize adults entering into polygamous religious marriages, even when the parties aren’t claiming any legal rights stemming from such a marriage. I think such a criminal prohibition violates the Free Speech Clause. But other articles discuss whether there should be a constitutional right to government recognition of polygamous marriage, much as the court is now considering whether there should be a constitutional right to government recognition of same-sex marriage. The article that most squarely endorses this view is Ronald C. Den Otter’s Three May Not Be a Crowd: The Case for a Constitutional Right to Plural Marriage (paragraph breaks added):

This Article takes seriously the substantive due process and equal protection arguments that support plural marriage (being able to marry more than one person at the same time). While numerous scholars have written about same-sex marriage, few of them have had much to say about marriages among three or more individuals.

As progressive, successful, and important as the Marriage Equality Movement has been, it focuses on same-sex marriage at the expense of other possible kinds of marriages that may be equally worthwhile. The vast majority of Americans still do not discuss plural marriage openly and fairly, as if the topic were taboo.

One of the goals of this Article is to convince readers that marriage in the future could be a much more diverse institution that does a better job of meeting individual needs. After all, one size may not fit all. Unfortunately, too often, scholars reduce plural marriage to the exploitation of women and the abuse of children. This approach makes it too easy to dismiss the possibility that a plural marriage might work better than the alternatives for at least some individuals in some circumstances.

Because the expansion of marriage to include same-sex couples is bound to cover a broader range of marital relationships, lawmakers, judges, and the rest of us eventually will have to decide which kinds of intimate relationships will be accorded legal status and which kinds will be left out. Today, a growing number of Americans reject the double standard when a state does not treat same-sex couples the same as opposite-sex couples when it comes to eligibility for marriage licenses. The strong dignity language of the recent Windsor decision indicates that future courts will be more skeptical of the rationale for limiting marriage to a man and a woman if it is predicated upon demeaning sexual minorities.

Another double standard, which is the focal point of this Article, concerns why the state allows almost all couples to marry for just about any personal reason that they happen to have. At the same time, all states continue to refuse to recognize any plural union. Those who care about gays and lesbians being discriminated against cannot ignore whether those who would marry multiple partners, if they were allowed to do so, are also being treated unfairly. The former kind of discrimination may be more widespread and worse than the latter, but that does not mean the latter is constitutionally permissible….

And here’s an excerpt from Stu Marvel, The Evolution of Plural Parentage: Applying Vulnerability Theory to Polygamy and Same-Sex Marriage (paragraph breaks added):

These plural forms of parentage indicate that we are in a period of marriage evolution, wherein multiple adult caregivers may have a potential claim on the right to parent a given child. This Article contends that, in step with the increasing acceptance of same-sex marriage, such an evolution must eventually confront the materially plural character of same-sex reproduction.

The dyadic nature of marriage is under pressure from plural forms of parentage and is in the process of fracturing to include de facto parents and dispersed “queer” families, as well as polygamous forms of union. Indeed, a vulnerability analysis demonstrates that such an outcome is not only likely, but emerges in direct response to the social and institutional vulnerabilities of the individual, the family, and the state.

As I will argue, within a society such as the United States, which depends heavily on the caregiving labor of the private family, the eventual recognition of same-sex marriage and polygamous unions is practically inevitable.

I’m skeptical of this position, but I thought I’d note it; for my own (complicated) views on whether recognition of same-sex marriage would materially increase the likelihood of recognizing polygamous marriages, see this article.