http://www.glad.org/doma/lawsuit/ This is a terrific law suit. Three surviving spouses have been denied federal benefits. This is pertinent and well directed.
And guess what. The DoJ will have to argue against it.
As to Smelt, they filed on everything under the sun so it either the law has to be argued or the standing. There isn't any way to defend it on any narrower grounds than they did.
"The amended complaint alleged that to the extent that California Family Code sections 300,6 301,7 and 308.58 preclude them from obtaining a marriage license, those sections violate: equal protection; due process; "the Right to Life, Liberty and the Pursuit of Happiness"; "the right to be free from an undue invasion of the Right to Privacy; ... the Ninth Amendment Right of Reservation of all Rights not Enumerated to the People, and the Right to Travel, and The Right of Free Speech." The complaint also asserted that section 308.5 violates the Full Faith and Credit Clause of the United States Constitution.9
4
Additionally, the complaint raised federal constitutional challenges to DOMA. Specifically, it alleged that Section 2 of DOMA (28 U.S.C. § 1738C)10 violates the United States Constitution's Due Process Cause (Fifth Amendment), equal protection rights (Fifth Amendment), the Right to Privacy, and the Full Faith and Credit Clause. Finally, it alleged that Section 3 of DOMA (1 U.S.C. § 7)11 violates the "liberty interests protected by the Due Process Clause"; discriminates "on the basis of gender" and "sexual orientation" in violation of equal protection; and violates "the privacy interests protected by the Right to Privacy."
http://altlaw.org/v1/cases/1139664