If you would like a good primer on the legal obstacles that same sex marriage still faces as proposed legislation for civil unions and marriage equality makes its way through state legislatures and the court system, this is a great article to read.
The bottom line: The simplest step would be to dismantle the Defense of Marriage Act, known as DOMA. But while there is a bill with growing support that would repeal the law, called the Respect for Marriage Act, it seems unlikely to get far in Congress. Instead, legal experts and gay advocates say, their better course is through the courts.
There are some landmark cases making their way through the system: The plaintiffs in two separate cases — which include seven couples and three individuals who have been denied federal benefits like Social Security payments and the right to file taxes jointly — prevailed in a lower court in Boston in 2010.
If the plaintiffs prevail, their victory should extend to all same-sex couples in the jurisdiction covered by the appeals court — which includes Massachusetts and New Hampshire, where gay marriage is legal; Rhode Island, which allows civil unions; and Maine and Puerto Rico. That means they would be eligible for federal benefits and the “full respect and recognition of the federal government” that heterosexual married couples receive.