Reuters/David McNew

Gay rights advocates secured another milestone victory on Thursday, when the US Court of Appeals for the First Circuit unanimously declared unconstitutional a federal law denying benefits to same-sex married couples that are otherwise available to opposite-sex married couples. This is the first federal law ever declared unconstitutional by an appellate court for discriminating against gays and lesbians, and it’s almost certainly headed for the Supreme Court. That’s a scary destination for any progressive legal claim these days, but for a variety of reasons, this case is a much better vehicle for gay rights advocates and the Supreme Court alike than the constitutional challenge to California’s ban on same-sex marriage, which the US Court of Appeals for the Ninth Circuit declared unconstitutional in February. Which case gets to the Court first may be a matter of luck. The Ninth Circuit decision is now awaiting a decision on a request for en banc review by a larger panel of that court, and will not be ripe for a petition for Supreme Court review until the Ninth Circuit resolves the en banc request. The First Circuit case, by contrast, could go directly to the Supreme Court. That’s good news for all concerned.

The law struck down in Massachusetts v. U.S. Dep’t of Health and Human Services, the Defense of Marriage Act, or DOMA, was enacted in the wake of a 1993 Hawaii Supreme Court decision declaring that Hawaii’s denial of marriage to same-sex couples might be unconstitutional. In a panic, Congress in short order and by large majorities passed DOMA, which among other things denies federal tax and Social Security benefits to same-sex married couples, reserving those benefits for marriages between a man and a woman, even where states recognize same-sex marriage on equal footing with opposite-sex marriage.

The challengers to the law maintain that it impermissibly discriminates on the basis of sexual orientation, and interferes with a realm traditionally reserved to the states—family law and the definition of marriage. The federal government initially defended the law, but, under President Obama, switched sides and argued that it is unconstitutional. Republican members of the House of Representatives, represented by former Solicitor General Paul Clement, intervened to defend the law. A unanimous panel comprised of judges appointed by Presidents Clinton, Reagan and George H.W. Bush, in a moderate, carefully reasoned and restrained opinion, found that the law did indeed violate equal protection.

The Justice Department and the plaintiffs had argued that because it discriminated on the basis of sexual orientation, the law should be subjected to more skeptical scrutiny than laws drawing other kinds of distinctions. The statute’s defenders maintained that it need only satisfy “rational basis” review, a highly deferential standard that upholds any law as to which one can imagine any rational justification.

The panel adopted neither view. It considered itself bound by an earlier decision of the First Circuit, which, in a challenge to the military’s “don’t ask, don’t tell” policy, declined to treat gays and lesbians as a “suspect class” warranting categorically heightened scrutiny. But the panel noted that the Supreme Court has on several occasions applied “rational basis” review with special care to laws that discriminate against historically disadvantaged groups and whose justifications were “thin, unsupported, or impermissible.” And it noted that because this federal law interfered with a traditional state domain, Congress should be obliged to offer justifications for its actions with “special clarity.”

In the end, the debate over the standard of review was less determinative than the simple fact that here, as with many laws treating gays and lesbians differently, there simply was no rational justification for the law. Congress said it sought to (1) defend traditional heterosexual marriage, (2) defend traditional notions of morality and (3) conserve scarce resources. But neither Congress nor the law’s defenders could explain how denying Social Security benefits to same-sex married couples would defend heterosexual marriage. As the court said, there is no reason to believe the denial of benefits would “affect the gender choices of those seeking marriage.”

The Supreme Court in Lawrence v. Texas, which declared unconstitutional Texas’s criminal ban on homosexual sodomy, said that mere moral disapproval is an insufficient justification for discrimination on the basis of sexual orientation. And the Court has also ruled that “saving money” is not a good enough reason for discriminating against a historically disadvantaged group.

The First Circuit recognized that its decision was virtually certain to be reviewed by the Supreme Court, and stayed the effect of its ruling until that time. I have written in detail in The New York Review of Books why this case would be a better case for Supreme Court review than the California gay marriage case. Suffice it to say here that the First Circuit’s reasoning is straightforward and moderate, has the assent of two Republican-appointed judges and, most importantly, does not call into question the validity of the many state laws restricting marriage to opposite-sex couples. Gay rights advocates are justifiably nervous about the Supreme Court addressing the ultimate question of gay marriage now, when only about six states recognize gay marriage, and more than thirty have laws affirmatively precluding its recognition. Historically, the Supreme Court has been a follower, not a leader, when it comes to expanding rights. That is all the more likely to be the case given the conservative makeup of the Court today. But as the First Circuit’s unanimous decision shows, even conservatives can find a lot not to like in this law.