Custom, Preference, or Nature? Mormon Polygamy, Same-Sex Marriage, and Natural Law Theory

Abstract

A central claim of natural law theory is that moral reality exists independently of human beliefs about that reality. Yet history is replete with natural law theorists who confused their beliefs about the natural law for the law itself. The 19th-century campaign against Mormon polygamy is a case study that echoed in recent debates about LGBTQ access to marriage. Nineteenth-century anti-polygamist arguments and contemporary defenses of traditional marriage each illustrate the dangers and pretensions of natural law theory.

Anti-polygamists justified their attacks on Mormon polygamy with appeals to Protestant Christian morality, a sexist theory of republican self-government, and White supremacy, rooting each of these in the natural law. Though anti-polygamists were confident of the objective truth of their premises, the passage of time exposed these premises as merely customary values held by 19th-century White Americans.

Natural law defenders of traditional marriage made the same mistake in a different way. They argued that the defining characteristic of marriage is reproductive sexual union, a definition now rejected by most Americans. Rather than mistaking widely held social conventions for the objective moral order, traditional marriage defenders mistook their sectarian religious beliefs about marriage for that order.

Natural law essentialism has been a source of oppression of both religious minorities and LGBT persons throughout history. In both cases, it prevented the protection of personal identity and the opening of private space for the individual pursuit of the good that liberalism supposedly protects. The ease with which we mistake our social or personal commitments for Nature suggests that the natural law is an unreliable justification for coercive laws.

Keywords: natural law, morality, polygamy, marriage, LGBTQ, Mormons, liberalism