When Christians warned that activists might use the legal argument in favor of same-sex marriage to justify polygamous marriage or consanguineous marriage (marriage of relatives), they were roundly accused of hysteria. But if the traditional vision of marriage as the union of one man and one woman is a specifically Christian model, as same-sex marriage advocates argue, and thus the support of traditional marriage is "forcing Christian beliefs on others," then the state cannot discriminate against other religious models of marriage without violating freedom of religion.
In legalizing only traditional marriages, in other words, the state would be siding with Christians against everyone else on what marriage should mean.
Such is the argument now on offer from the Mormon stars of a reality show called Sister Wives (see "Little love," April 9, 2011). Although the Church of Jesus Christ of Latter Days Saints banned polygamy over a century ago, separatists continue the practice. Sister Wives, which began airing on TLC in 2010, introduced millions of viewers to the family of Kody Brown and his four wives. According to their attorney, polygamy is a "deep-seated religious belief" for the Browns, who merely seek "equal treatment with other citizens in living their lives according to their beliefs."
Mormon polygamists are not alone. Practitioners of modern paganism defend polygamy online, making the same argument that laws against polygamy essentially discriminate against their religious beliefs. And defenders of consanguineous marriage argue that the chances of genetic defects are higher among older parents than they are when cousins reproduce.
When laws upholding traditional marriage are seen as "privileging" Christian beliefs, the doors are thrown open to anyone who can argue that his faith blesses marriage in nontraditional forms.