For several years now, I have sought to vindicate what I call feminist fundamentalism, which I define as an uncompromising commitment to the equality of the sexes as intense and at least as worthy of respect as, for example, a religiously or culturally based commitment to female subordination or fixed sex roles. As I have argued, both individuals and nation-states can have feminist fundamentalist commitments that, like the religious commitments to which they can fruitfully be analogized, may differ somewhat in content as well as in character. Although all feminists repudiate female subordination, for example, some may seek equality in separate spheres, whereas others insist instead that “fixed notions concerning the roles and abilities of males and females” are anathema. Although, in the late twentieth century, feminist fundamentalist commitments of the latter kind were central to the constitutionalization of the law of marriage in the United States and elsewhere, more recent disputes at the intersection of constitutional and family law in Western constitutional democracies have foregrounded other concerns, including sexual orientation nondiscrimination, religious liberty, and respect for cultural diversity.

In this chapter, I analyze what a feminist fundamentalist perspective might bring to one of these ongoing disputes, the question of whether same-sex couples have a constitutional right to marry. Taking the bulk of my examples from state constitutional cases in the United States, I shall argue that the growing trend toward rejection of a constitutional prohibition on sex discrimination as one basis for invalidating restrictions on same-sex marriage has broader adverse consequences for the sexual liberty and equality of all individuals, particularly but not exclusively for heterosexual women from a feminist perspective.