and Federal Governments, emphasizing that DOMA "rejects the long-established precept that the incidents, benefits, and obligations of marriage are uniform for all married couples within each State." Ante, at 18. But there is no such departure when one State adopts or keeps a definition of marriage that differs from that of its neighbor, for it is entirely expected that state definitions would "vary, subject to constitutional guarantees, from one State to the next." Ibid. Thus, while "[t]he State's power in defining the marital relation is of central relevance" to the majority's decision to strike down DOMA here, ibid., that power will come into play on the other side of the board in future cases about the constitutionality of state marriage definitions. So too will the concerns for state diversity and sovereignty that weigh against DOMA's constitutionality in this case. See ante, at 19.
It is not just this central feature of the majority's analysis that is unique to DOMA, but many considerations on the periphery as well. For example, the majority focuses on the legislative history and title of this particular Act, ante, at 21; those statute-specific considerations will, of course, be irrelevant in future cases about different statutes. The majority emphasizes that DOMA was a "system-wide enactment with no identified connection to any particular area of federal law," but a State's definition of marriage "is the foundation of the State's broader authority to regulate the subject of domestic relations with respect to the '[p]rotection of offspring, property interests, and the enforcement of marital responsibilities.'" Ante, at 22, 17. And the federal decision undermined (in the majority's view) the "dignity [already] conferred by the States in the exercise of their sovereign power," ante, at 21, whereas a State's decision whether to expand the definition of marriage from its traditional contours involves no similar concern.
We may in the future have to resolve challenges to state
