A central point of contention in the national debate over same-sex marriage is the importance of preserving tradition. That debate also features prominently in constitutional litigation over bans on same-sex marriage. Opponents of such bans argue that tradition is an illegitimate justification for the bans, while defenders of traditional marriage contend that tradition is not only a legitimate justification, but is in fact sufficiently important to withstand heightened judicial scrutiny.

This Article assesses tradition as a justification for laws challenged on equal protection grounds, with a focus on laws that limit marriage to opposite-sex couples. The Article makes two main points. First, it concludes that a state’s interest in preserving tradition— including the tradition of opposite-sex marriage—is probably legally sufficient to survive the most deferential standard of rational basis review under the Equal Protection Clause.

Second, this Article argues that courts should nonetheless view tradition with skepticism when it is offered to justify laws challenged on equal protection grounds. Tradition exhibits certain features, or “indicia of suspectness,” that counsel skepticism. Those features include tradition’s speculative utility, rhetorical appeal, and manipulability. Additionally, tradition is especially suspicious when offered to justify laws that burden a group toward whom there has been a cultural shift from widespread societal disapproval in the past to substantial public tolerance today. In such circumstances, tradition may serve as a convenient justification for people who are actually motivated by now-repudiated attitudes toward the burdened group. For bans on same-sex marriage, this Article contends, courts should invalidate such laws unless, after careful scrutiny, courts are satisfied that the laws are motivated by legitimate, non-tradition-based interests.