This document is an amicus brief in support of petitioners in four Supreme Court cases challenging state bans on same-sex marriage. It argues that equal access to civil marriage for same-sex couples promotes conservative values like stability, mutual support, and obligation. It further argues that excluding same-sex couples from civil marriage violates the Fourteenth Amendment because there is no legitimate fact-based rationale for such bans. The brief contends that even tradition and caution in the face of societal change are not sufficient justifications to sustain the constitutionality of marriage bans. It urges the Court to ensure that governments do not deny same-sex couples the rights and responsibilities of civil marriage.