The public is currently engaged in an active political debate over whether same-sex couples should be allowed to marry. That question has also given rise to litigation. In this case, petitioners, who oppose same-sex marriage, ask us to decide whether the Equal Protection Clause “prohibits the State of California from defining marriage as the union of a man and a woman.” Pet. for Cert. i. Respondents, same-sex couples who wish to marry, view the issue in somewhat different terms: For them, it is whether California—having previously recognized the right of same-sex couples to marry—may reverse that decision through a referendum.
Federal courts have authority under the Constitution to answer such questions only if necessary to do so in the course of deciding an actual “case” or “controversy.” As used in the Constitution, those words do not include every sort of dispute, but only those “historically viewed as capable of resolution through the judicial process.” Flast v. Cohen, 392 U. S. 83, 95 (1968). This is an essential limit on our power: It ensures that we act as judges, and do not engage in policymaking properly left to elected representatives.
For there to be such a case or controversy, it is not enough that the party invoking the power of the court have a keen interest in the issue. That party must also have “standing,” which requires, among other things, that it have suffered a concrete and particularized injury. Because we find that petitioners do not have standing, we have no authority to decide this case on the merits, and neither did the Ninth Circuit.