Last week, the U.S. Court of Appeals for the Sixth Circuit in Cincinnati issued a a ruling that will result in marriage rights being denied to same-sex couples in four states. In the short term, this is unfortunate. But in the longer term, this could prove to be excellent news for gay and lesbian rights.

That's because the Sixth Circuit's decision will force the Supreme Court to issue a decision that will probably be favorable to same-sex marriage. Judge Jeffrey Sutton's majority opinion only demonstrates why bans on gay marriage deserve to fall.

Crucially, the appellate court's opinion created a split among circuit courts on the constitutionality of same-sex marriage. Before the Sixth Circuit, every circuit court to have decided the issue had held that bans on same-sex marriage were unconstitutional, making it easier for the Supreme Court to continue to duck the question.

But the Supreme Court will rarely fail to intervene to resolve a division between circuit courts on a major constitutional question. It's now possible that the Supreme Court will decide the issue this term, and the justices will have to intervene by next term at the latest.

Most court observers feel that the Supreme Court will rule that state bans on same-sex marriage are unconstitutional. Judge Sutton's majority opinion helps to illustrate why this will happen. This isn't because the opinion is unusually weak — Sutton is one of the sharpest of the conservative judges George W. Bush appointed to the federal courts, and he makes the strongest case he can. All of this makes it all the more damning that his opinion manifestly fails to persuade.

Perhaps the biggest tell is the amount of space Sutton devotes to questions about the philosophical justifications for judicial review and its role in democracy, as if he were an undergraduate trying to pad out a term paper. Sutton goes on at some length defending the principle of judicial restraint and arguing that issues of national import should be "democratically" decided by state legislatures rather than by federal courts. This throat-clearing caused Judge Martha Craig Daughtrey to remark in the opening lines of her dissent that "[t]he author of the majority opinion has drafted what would make an engrossing TED Talk or, possibly, an introductory lecture in Political Philosophy. But as an appellate court decision, it wholly fails to grapple with the relevant constitutional question in this appeal."

The real question is whether these discriminatory state classifications can be consistent with the 14th Amendment's guarantee of the equal protection of the laws. On this question, Sutton is part of a small minority of federal court judges for a reason.

Sutton relies a great deal on Baker v. Nelson, a one-line order from the Supreme Court dating from 1972 asserting that state refusals to issue marriage licenses to same-sex couples did not present a "substantial federal question." But after several major subsequent Supreme Court opinions upholding gay and lesbian rights, it is no longer tenable to pretend that this remains the controlling precedent. As Judge Daughtrey observes, "[I] ever there was a legal 'dead letter' emanating from the Supreme Court, Baker v.Nelson is a prime candidate. It lacks only a stake through its heart."

In other words, Baker isn't nearly enough; bans on same-sex marriage need to survive the greater scrutiny the Supreme Court has given to discrimination against gays and lesbians in the interim, including last year's ruling to strike down the Defense of Marriage Act.

Sutton's arguments on the crucial point, however, are interesting. Sutton concedes that if bans on same-sex marriage are motivated by animus against gays and lesbians, they cannot pass even rational basis review. This is an advance on conservative thinking on this issue. Supreme Court Justice Antonin Scalia, for example, infamously thundered in his dissent in the 1996 case Romer v. Evans that "[t]he Court's opinion contains grim, disapproving hints that Coloradans have been guilty of 'animus' or 'animosity' toward homosexuality, as though that has been established as Unamerican."

Sutton takes a different approach, admitting that there has been invidious discrimination against gays and lesbians and that this would be constitutionally problematic, but denying that limiting marriage to opposite-sex couples reflects such animus.

This argument is less hateful than Scalia's, but it's no more persuasive. To argue that the exclusion of same-sex couples from marriage exists in splendid isolation from systematic discrimination against gays and lesbians is implausible in the extreme. And it's even less tenable in this context, because all four of the states whose laws are under review have reaffirmed their bans on same-sex marriage through statute or constitutional amendment within the last decade.

Finally, Sutton reverts to the fancy theoretical means conservatives use to justify exclusionary traditions: originalism. One conservative legal blogger argues that Sutton's claim that "[n]obody in this case…argues that the people who adopted the Fourteenth Amendment understood it to require the States to change the definition of marriage" should "be the beginning and end of the analysis."

Let's leave aside the many problems with the originalist approach to constitutional interpretation. The fact is that relying on the particular policy expectations of individual framers isn't even good originalism. The framers and ratifiers of the Fourteenth Amendment enacted a general principle of equal protection, not the specific policy expectations of individual lawmakers.

Indeed, most framers and ratifiers of the Fourteenth Amendment thought that segregated schools and bans on interracial marriage were consistent with the equal protection of the laws, but this doesn't make Brown v. Board of Education and Loving v. Virginia wrong. The only question is whether the Fourteenth Amendment's equal protection principles are consistent with excluding gays and lesbians from the fundamental right to marry. The answer to that question is "no."

The most fundamental problem with Sutton's argument, as Judge Daughtrey eloquently observes, is that "the majority treats both the issues and the litigants here as mere abstractions" while not "recognizing the plaintiffs as persons, suffering actual harm as a result of being denied the right to marry where they reside or the right to have their valid marriages recognized there."

All of the hand-waving about federalism and judicial rights cannot disguise the fact that this case involved victims of unconstitutional, invidious discrimination that does very real harm to their lives. Hopefully, the Supreme Court will correct this injustice sooner rather than later.