The United States Court of Appeals struck down Section 3 of the Defense of Marriage Act as unconstitutional today with a written opinion which found that there was no permissible federal interest in Congress’ denial of federal benefits to same sex couples married in Massachusetts. The court also concluded that federalism concerns precluded them from upholding the restriction since the law burdens the choice of states as to how regulate marriage laws by having them risk federal funding and forcing them to assume new administrative burdens.  

The DOMA was passed in 1996 in response to Hawaiian legislation legalizing same sex marriage. The full opinion is available at the above link.