Richard Socarides reflects on the ruling:
For now, the ruling from the court today is a great victory for gay-rights advocates. It would have been unheard of less than ten years ago to think that one could get a federal appeals court—and an important one—to rule so broadly in favor of the rights of gay Americans. That it is also a victory for Edie Windsor, an eighty-three-year-old widow who was determined to fight, makes it all the sweeter. She has said, “It’s so hard to say why it matters, why marriage is different. But marriage is different. It has to do with our dignity altogether.”
Julie Bolger unpacks the decision:
[T]he Second Circuit became the first federal appeals court to hold that laws that classify individuals based on sexual orientation should receive a more exacting level of judicial review, known as “heightened scrutiny.” The First Circuit Court of Appeals in Boston, which ruled DOMA unconstitutional in the Gill case last May, did not apply heightened scrutiny.
Scott Lemieux drills down:
[T]oday's opinion is important because the theory underlying the court's holding goes much further than the First Circuit did. The Supreme Court has developed a three-pronged approach to applying the equal protection clause of the Fourteenth Amendment. Under this framework, racial classifications have been held to require "strict scrutiny," under which the classification is constitutional only if necessary to achieve a compelling state objective. Most classifications require merely "rational basis" scrutiny—that is, the state only has to show that a classification bears any plausible rational relationship to a legitimate state interest. In practice, laws rarely survive strict scrutiny and rarely fail to survive rational basis analysis. Gender classifications are subjected to an intermediate level of heightened scrutiny that requires more justification than rational basis but less than strict scrutiny.
As of now, sexual orientation is, at least nominally, a "rational basis" category, and the First Circuit opinion found that DOMA was unconstitutional under that standard.