state's decision as to how to shape its own marriage laws." Massachusetts, 682 F.3d, at 12–13. The Act's demonstrated purpose is to ensure that if any State decides to recognize same-sex marriages, those unions will be treated as second-class marriages for purposes of federal law. This raises a most serious question under the Constitution’s Fifth Amendment.
DOMA's operation in practice confirms this purpose. When New York adopted a law to permit same-sex marriage, it sought to eliminate inequality; but DOMA frustrates that objective through a system-wide enactment with no identified connection to any particular area of federal law. DOMA writes inequality into the entire United States Code. The particular case at hand concerns the estate tax, but DOMA is more than a simple determination of what should or should not be allowed as an estate tax refund. Among the over 1,000 statutes and numerous federal regulations that DOMA controls are laws pertaining to Social Security, housing, taxes, criminal sanctions, copyright, and veterans' benefits.
DOMA's principal effect is to identify a subset of state-sanctioned marriages and make them unequal. The principal purpose is to impose inequality, not for other reasons like governmental efficiency. Responsibilities, as well as rights, enhance the dignity and integrity of the person. And DOMA contrives to deprive some couples married under the laws of their State, but not other couples, of both rights and responsibilities. By creating two contradictory marriage regimes within the same State, DOMA forces same-sex couples to live as married for the purpose of state law but unmarried for the purpose of federal law, thus diminishing the stability and predictability of basic personal relations the State has found it proper to acknowledge and protect. By this dynamic DOMA undermines both the public and private significance of statesanctioned same-sex marriages; for it tells those couples,