Defense of Marriage Act
The Defense of Marriage Act (DOMA) is a 1996 U.S. law that effectively bans same-gender marriage on a Federal level, by stating that the Federal government will only recognize opposite-gender marriages for the purposes of public policy, meaning that even if a same-gender couple is legally married in a particular state, they cannot receive any Federal spousal benefits such as Social Security. DOMA also allows individual states to refuse to recognize same-gender marriages performed elsewhere.
Fourteen Senators - all Democrats - voted against DOMA: Akaka (D-HI)
Barbara Boxer (D-CA), Russ Feingold (D-WI), Dianne Feinstein (D-CA), Daniel Inouye (D-HI), Ted Kennedy (D-MA), Bob Kerrey (D-NE), John Kerry (D-MA), Carol Moseley Braun (D-IL), Patrick Moynihan (D-NY), Claiborne Pell (D-RI), Chuck Robb (D-VA), Paul Simon (D-IL), Ron Wyden (D-OR). One Democratic Senator did not vote: David Pryor (D-AR)
Senate Roll Call Vote
House Roll Call Vote
Some attorneys believe DOMA may be unconstitutional because it goes beyond the powers granted to Congress by the Full Faith and Credit clause of the Constitution that grants Congress the authority to "prescribe...the Effect" which the laws of one state have in another. During the next several years cases challenging DOMA are likely to be heard by the Federal court system. DOMA inspired many state-level laws and constitutional amendments to forestall challenges to the federal law. The number of states that have not done so shrink every year: as of November 2005, they are Maryland, New Hampshire, Oregon, New Mexico, Wisconsin, Wyoming, New Jersey, New York, Vermont, Rhode Island, Massachusetts, and Connecticut.
Although Bill Clinton signed the Defense of Marriage Act into law during his re-election campaign in 1996 and vehemently opposed same-sex marriage, he did not mention the law in his 2004 memoir, My Life.
In a June 1996 interview in the gay and lesbian magazine The Advocate, Clinton said: " I remain opposed to same-sex marriage. I believe marriage is an institution for the union of a man and a woman. This has been my long-standing position, and it is not being reviewed or reconsidered." 
The proposed Federal Marriage Amendment is an effort to circumvent constitutional challenges to DOMA and broaden its provisions.