June 26, 2015 was a major victory for the gay rights movement as same-sex marriage was legalized in all fifty states via Obergefell v. Hodges. While issues of LGBT discrimination and social stigma still need to be addressed in American society, a large step in the right direction was taken. The debate that has been triggered as a result is whether polygamous marriage should also become illegal. On a worldwide level, polygyny (a man being able to marry more than one wife) is legal in the Middle East (except for Israel), most of Africa, and some other countries in Asia. Can an argument of marriage equality make polygamy a legal reality in the United States?
A little bit of legal background first. Polygamy was practiced in the mid-nineteenth century by those of the Mormon faith. In 1879, the Supreme Court delivered the opinion in Reynolds v. United States that polygamy is illegal in the United States. In 1890, the Mormon church removed polygamy from its doctrine, and to this day, The Latter Day Saints' official position is that marriage is between one man and one woman. There are still some fundamentalist Mormons that practice polygamy: anywhere between a few hundred and 10,000 individuals by the state of Utah's estimation. There are even some Muslims in this country who also practice polygyny. The number of those who are presently in polygamous relations is very small relative to the overall population.
There is more than the legal status quo getting in the way. Even with the progress being made on LGBT rights, polygamy is still seen as morally acceptable by only 16 percent of the population. It was in single-digit territory over a decade ago, but still has a long way to go before reaching a level of acceptability in the United States. I would argue that since polygamy has strong ties to religious fundamentalists, there will be many who will attach guilt by association. While there might be a lot of parallels by allowing for consenting adults to enter a polygamous marriage, polygamy is not a sexual orientation.
Another factor that it is not in favor of polygamists is that most people don't know polygamists. With the fight for same-sex marriage (which we can now simply refer to as marriage), it was easier to win the minds and hearts of Americans because you would be hard pressed to not find at least one family member, friend, co-worker, or colleague who is gay. As already mentioned, polygamists tend to be isolated, religious fundamentalists, which makes it harder for individuals to sympathize with polygamists. It is also much easier to sympathize with the idea of "I want to make a full commitment to the person whom I love" than "my needs are not fulfilled with just one person." Without a large-scale social movement, legalizing polygamous becomes nigh impossible.
There are also legal complications that do not exist with same-sex, monogamous marriage: the tax code, benefits structure, divorce and child custody. These would be all the more ambiguous and complicated as a result of legalizing polygamy. Granted, it would be less complicated if the government didn't offer such benefits (an argument that doesn't work as well with adjudicating divorce and child custody). However, we live in a world in which the government feels the need to provide benefits, so until the government reverses that trend, polygamy becomes more complicated for tax and regulatory purposes. Another legal snag that polygamy proponents would hit is rational-basis review. The reason why same-sex marriage was able to gain legal traction is because same-sex marriage opponents could not surpass this very low bar and explain why same-sex marriage would harm others. As I will now illustrate, polygamy proponents do not have that luxury.
The problem with polygamy being around for so long is that it has been tried and tested, only to prove that it is statistically more likely to fail than monogamy. Even the Bible illustrates how problematic polygamy can be! Amongst other ill effects, polygamy increases violence and poverty (Henrich, 2012), increases the risk of heart attacks by fourfold, causes overbreeding (Mbirimtengerenji, 2007), stymies academic growth of children (Adenike, 2013), and is more likely to cause mental health issues (Al-Krenawi, 2013). Opponents also argue that polygamy skews sex ratios. India and China are going to be running into their own sex-ratio issues down the road, so we shouldn't ignore disproportionate sex ratios. However, how concerned should we be about skewed sex ratios in the United States? For one, informal polygamous relations take individuals out of the dating pool, as well. As has been previously mentioned, some will enter polygamous relations regardless of the the de jure ban. What should be of concern is bringing it out of the margins of society so it's easier to determine such abuses as secretive, non-consensual multiple-marriage situations.
Jealousy, which shows up in polygamous relations via intra-sexual competition, plays a major role in why polygamous relations are more likely to turn out poorly than monogamous ones (Jankowiak et al., 2005). To quote a Slate article referring to why polygamy was as normative as it was: "Women shared men because they had to. The alternative was poverty. As women gained power, they began to choose what they really wanted. And what they wanted was the same fidelity that men expected from them." Two is not an optimal number in marriage strictly for abating jealousy. It is also an optimal number since polygamy has this tendency to fracture paternal investment in children.
Conversely, let's consider that marriage itself is on the decline. People have a hard enough time finding one person, so a fortiori, people would have an even harder time finding multiple spouses. To put this idea in more economic terms, the marriage market is like any other market. Legalizing polygamy would shift out the demand curve for spouse (most presumedly wives). An increase of demand without an increase of supply means that it is more expensive to find multiple spouses. Without [a man] offering something of higher value, the odds that a woman would enter a polygamous relationship is low. Another point to consider is that over the past century, marriage has become more about consumption compatibility (i.e., marrying someone because you get along, not because of the outdated notions that the "husband is the breadwinner" or "the wife has to stay at home"). Polygamy is most likely to rise when the supply of women exceeds the demand. Given that marriage has become an institution more based on consumption compatibility, supply will most probably not exceed demand. Between the economics and overall decline of the institution of marriage, I wouldn't worry about polygamy becoming prevalent even if it were legalized.
Postscript: While allowing for consenting adults to enter a voluntary, polygamous transaction has some parallels to the fight for same-sex couples in marriage equality, there are enough dissimilarities where polygamy is not gaining any traction in the foreseeable future. None of the modern, egalitarian societies have a broad social movement legalizing polygamy, which should put opponents' minds at ease. As for whether it should be legalized, polygamy could be banned based on a rational-basis review, which is something that same-sex marriage could not. Polygamy has adverse effects both on those involved in the marriage and society as a whole. On the other hand, we live in a country that was based on the idea of life, liberty, and the pursuit of happiness.
For instance, I think that if people are going to have children, they should get married first because statistically speaking, it's more difficult otherwise. Just because I disagree with someone's life choice does not mean I should get in the way of what stupidity consenting adults put each other through. Statistically speaking, having children before being married is a bad idea, and so is polygamy. At the end of the academic debating, I would say that people should be allowed to make whatever misguided decisions they want to make, even if that means entering a polygamous relationship. Even if it were legalized today, I would not be worried because, as already illustrated, I cannot foresee how polygamy would become prevalent.
Whatever the outcome might be, one thing I can assuredly say is that polygamy is not the new fight for marriage equality.