This paper examines constitutional issues concerning same-sex marriage. Although same-sex relations concern broader ethical issues as well, I set these aside to concentrate primarily on legal questions of privacy rights and equal protection. While sexual orientation is neither a suspect classification like race, nor a quasi classification like gender, there are strong reasons why it should trigger heightened scrutiny of legislation using sexuality as a standard of classification. In what follows, I argue that equal-protection doctrine is better suited for including (...) same-sex couples where legal benefits and burdens of marriage are at stake. (1) I reconstruct arguments from privacy and the controversial ruling of Bowers v. Hardwick but discount this strategy for problematic legal reasons. (2) In order for equal protection to apply, sexual orientation must meet the criteria of suspect classification that the Court has established. (3) Since sexual orientation meets these criteria, heightened scrutiny should be applied to such legislation on equal-protection grounds. (4) Finally, I rely on some familiar Rawlsian arguments of public justification that demonstrate why this extension of marriage rights is consistent with basic constitutional principles. (shrink)