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.” 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.” 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.
We have repeatedly held that such a “generalized grievance,” no matter how sincere, is insufficient to confer standing. A litigant “raising only a generally available grievance about government—claiming only harm to his and every citizen’s interest in proper application of the Constitution and laws, and seeking relief that no more directly and tangibly benefits him than it does the public at large—does not state an Article III case or controversy.”
Petitioners argue that the California Constitution and its election laws give them a “‘unique,’ ‘special,’ and ‘distinct’ role in the initiative process—one ‘involving both authority and responsibilities that differ from other supporters of the measure.’” … True enough—but only when it comes to the process of enacting the law. Upon submitting the proposed initiative to the attorney general, petitioners became the official “proponents” of Proposition 8.
But once Proposition 8 was approved by the voters, the measure became “a duly enacted constitutional amendment or statute.” … Petitioners have no role—special or otherwise—in the enforcement of Proposition 8.
Neither the California Supreme Court nor the Ninth Circuit ever described the proponents as agents of the State, and they plainly do not qualify as such.