What has been explained to this point should more than suffice to establish that the principal purpose and the necessary effect of this law are to demean those persons who are in a lawful same-sex marriage. This requires the Court to hold, as it now does, that DOMA is unconstitutional as a deprivation of the liberty of the person protected by the Fifth Amendment of the Constitution.
— Excerpt from the majority opinion in United States v. Windsor, authored by Justice Anthony Kennedy and joined by Justices Ruth Bader Ginsburg, Sonia Sotomayor, Elena Kagan and Stephen Breyer.