This chapter argues that evaluating the arguments the parties made in Loving v. Virginia (1967), the iconic case in which the Supreme Court struck down Virginia’s anti-miscegenation law, aids in understanding puzzles about bigotry. Virginia attempted a modern, sociological defense of its racist law. Loving illustrates the role of generational moral progress in constitutional interpretation: laws justified by appeals to nature, God’s plan for the races, and children’s well-being were repudiated as rooted in racial prejudice, intolerance, and white supremacy. The chapter then considers Loving’s crucial (but contested) role in constitutional challenges to bars on same-sex marriage, first analyzing the successful challenge to Virginia’s defense of marriage law. It then analyzes the majority opinion in Obergefell v. Hodges, holding that same-sex couples have a fundamental right to marry; the dissenters argued Loving was inapt. The chapter concludes by discussing the role of moral progress and new insight in constitutional interpretation.