Obergefell

Majority reasoning

The majority reasoned that the right to marry is fundamental under the Due Process Clause, resting on four principles: personal autonomy in intimate choices, the unique importance of a two-person union, the safeguarding of children and family structures, and marriage's role as a keystone of the social order—all of which apply equally to same-sex couples. It rejected the argument that fundamental rights must be defined narrowly by historical practice, noting that prior right-to-marry cases like Loving, Zablocki, and Turner did not ask about a narrow "right to interracial marriage" or similar but addressed the right to marry generally. The Court also found the marriage bans violate equal protection because they deny same-sex couples the same legal treatment given opposite-sex couples without adequate justification, and it directly rejected the argument that same-sex marriage would harm opposite-sex marriage rates, calling that claim unsupported and illogical. The majority concluded that individuals need not wait for legislatures to act when a fundamental right is at stake, and overruled Baker v. Nelson.

Dissent reasoning

Chief Justice Roberts, joined by Scalia and Thomas, argued the majority's decision was an act of judicial will rather than legal judgment, disregarding the Constitution's silence on marriage and centuries of unbroken tradition defining it as between a man and a woman. He argued precedents like Loving, Zablocki, and Turner addressed restrictions on marriage as traditionally defined, never a right to redefine marriage itself, and that the majority's approach echoes the discredited substantive-due-process reasoning of Lochner v. New York. Roberts warned the ruling forecloses democratic debate that was actively working through legislatures and referenda, and raised concerns about unresolved religious liberty conflicts. Justice Scalia, joined by Thomas, separately objected to what he called the Court seizing lawmaking power from the people, arguing the Fourteenth Amendment's ratifiers never understood it to bar traditional marriage laws, and criticizing the opinion's writing style as pretentious. Justice Thomas, joined by Scalia, argued that "liberty" in the Due Process Clause historically meant only freedom from governmental restraint, not entitlement to government-conferred benefits like marriage licenses, and that the majority's decision to override the political process endangers both self-government and religious liberty. Justice Alito, joined by Scalia and Thomas, argued the newly announced right to same-sex marriage lacks deep roots in history or tradition as required by Glucksberg, that the traditional link between marriage and procreation supplies a rational basis for states' definitions, and that the ruling will be used to marginalize and stigmatize people who hold traditional views on marriage.