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

Second, the article argues, courts should nonetheless view tradition with skepticism when 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, the article contends, courts should invalidate such laws unless, after careful scrutiny, courts are satisfied that legitimate, non-tradition-based interests actually motivated them.