As Californians await the outcome of the Prop 8 trial, a federal court in Boston will hear a lawsuit tomorrow that challenges the Defense of Marriage Act (DOMA.) Brought by lawyers at GLAD (Gay & Lesbian Advocates & Defenders), the equal protection claim represents same-sex couples who have married in Massachusetts – but are denied federal benefits, such as Social Security survivor benefits. Even as states find that gays have a fundamental right to marry, we still do not have real marriage equality if DOMA is on the books – giving this case a more historic significance. And while the Justice Department has toned down its rhetoric defending the law (they no longer equate gay marriage with incest and pedophilia), the Obama Administration still defends Part 3 of DOMA – which says that federal benefits cannot be extended to same-sex couples. Using circular logic, their legal brief argues that a constitutional “right to marry” does not include a “right to marriage benefits” – proving that LGBT activists still have a long way to go.

The Prop 8 trial – which has been extensively covered by the Courage Campaign through its trial tracker – has been significant because the very essence of homophobia has been put on trial. But it’s always been risky taking such a case to federal court. As I argued when the Prop 8 trial began in January, going to federal court was inevitable – but a more proper course of action would be to first challenge DOMA on behalf of gay couples married in states where it is legal. Which is what we have here.

The lawsuit, Gill vs. Office of Personnel Management, represents a group of same sex couples in Massachusetts who married legally – but have been denied various federal benefits. DOMA bars the federal government from recognizing any gay marriage or civil union, even if their state does. While gays in California could marry before Prop 8, they still lacked full marriage rights. “Our case rests on equal protection,” said GLAD lawyer Mary Bonauto. “DOMA takes one class of married people in Massachusetts, and treats them differently.”

Unlike the separate challenge to DOMA filed on behalf of California couples (which was dismissed because the plaintiffs had not applied for federal benefits), the GLAD lawyers have done their homework with their clients – so the case should survive any procedural hurdles. Again, this puts the Obama Administration in the unenviable task of defending a law they are on record opposing. Now, there’s no way to avoid debating the substance.

In June, the Justice Department replied to the California suit by defending DOMA on the merits – in a highly offensive brief that equated gay marriage with incest and pedophilia. This fueled a public outrage in the LGBT community, but what was less heavily reported was how they defended Part 3 of DOMA. Calling it a “cautious policy of federal neutrality towards a new form of marriage,” the Obama Administration said that DOMA’s section barring the federal government from recognizing gay couples “does not discriminate against gays.”

Now, the Justice Department has been careful to start off by saying it “does not support DOMA as a matter of policy, believes it is discriminatory, and supports its repeal.” But as a matter of course, the Obama Administration insists that it must defend existing laws on the books. They have disavowed reasons cited in the 1996 Congressional record for passing DOMA (where Republican politicians spoke disapprovingly of homosexuals), but insist that sexual orientation is not a “suspect class” – so as long as any rationale can be dreamed up to justify DOMA, it passes a “rational basis” test under equal protection.

And in its reply brief, the Obama Administration uses circular logic in a way that only Joseph Heller – author of Catch 22 – would appreciate. Marriage is a constitutional right, they acknowledge, but there is “no fundamental right to federal benefits based on marital status.” Unlike the Prop 8 case, where plaintiffs argue that gays are being denied the right to marry, no one here disputes that Massachusetts couples have that right. The only question is whether they have a right to the benefits of marriage. In other words, gays in Massachusetts who fought for the right now only have it on paper.

This could set an infuriating precedent. Opponents of gay marriage always say that civil unions are an adequate substitute, as long as they grant same-sex couples all of the same benefits as marriage. States like California, Washington and New Jersey have expanded their civil unions statutes to grant all the same rights that state law allows – and in those states, gays must explain how the word “marriage” is essential. But now Massachusetts couples are told they can have the word “marriage,” just not the right to equal benefits.

It’s an untenable position legally – and the longer the White House drags its feet on a repeal of DOMA, the more they will feel compelled to make these arguments in court. Far from just a legal problem, it is a political problem for the Obama Administration.

President Bill Clinton – who signed DOMA in 1996 for crass political reasons – now admits that it is time to repeal it. Even Bob Barr, the right-wing former Congressman who authored DOMA, now says it should be scrapped. The only people against repealing DOMA is the religious right. If Obama does not move on a political solution fast, it will continue to give him headaches.

Paul Hogarth has a J.D. from Golden Gate University. He is an attorney licensed to practice law in California, but this piece is not intended as legal advice. He was a summer intern for Equality California in 2005, organized volunteers in 2009 for the “No on 1” campaign in Maine, and has helped live-blog the Prop 8 trial for the Courage Campaign.