I think it was Robin Williams who observed that all marriage is same-sex marriage, because it's always the same sex. But seriously, folks...
Attorney General Eric Holder recently announced that while the Obama administration would continue to enforce the federal Defense of Marriage Act (DOMA), the Justice Department had concluded that Section 3 of the Act was probably unconstitutional, and its lawyers would no longer defend it in court. Section 3 is the part that requires the federal government not to recognize same-sex marriages even when they are valid under state law and despite marriage always having been a matter of state law.
Contrary to some complaints from the right, other administrations, including those of Presidents Truman, Eisenhower, Kennedy, Ford, Reagan, Clinton, and both Bushes, have likewise declined to defend laws they deemed unconstitutional. For more legal details, see Nina Totenberg 's report on differing opinions of presidential obligations and Walter Dellinger's explanation of just what the administration did and why.
One case in which the Justice Department won't be defending DOMA concerns a woman named Thea Spyer who died in 2009, leaving a substantial inheritance to her spouse and companion of more than 40 years, Edith Windsor. Had Windsor been a man, the spousal exemption would have made the tax bill zero. Instead, because DOMA requires the IRS to pretend that the two women weren't legally married in their state of residence despite the fact that they were, the tax was more than $363,000.
Whatever one's views on the estate tax in general, a lot of people find it plainly unfair that a legally married couple devoted to one another for four decades should be denied a tax break that was permitted, for example, to the estate of J. Howard Marshall, who died 13 months after marrying a dancer (Anna Nicole Smith) he met in a strip club and with whom he reportedly never actually lived.
Over the past couple of decades there has been a sea change in public attitudes about same-sex relationships and same-sex marriage, paralleling a similar shift nearly half a century earlier away from racism and opposition to mixed-race marriage. Recent polling by the Pew Center for the People and the Press shows the U.S. public now almost evenly split, with 46% opposed and 45% in favor of same-sex marriage, though just 15 years ago the same poll had opponents outnumbering supporters 65-27. Even in relatively conservative North Carolina, two separate, credible recent polls indicated an absolute majority in favor of either same-sex marriage or civil unions.
Having long recognized changing public attitudes, opponents of same-sex marriage have shifted from open condemnation of homosexuality to a more reasonable-sounding "defense of marriage" stance, insisting that legal recognition of same-sex unions would somehow hurt traditional marriage and families, which of course nobody wants.
But, in Scandinavia, where same-sex marriage and fully equivalent civil unions have the longest history, legal recognition for same-sex couples was followed by a marked increase in traditional marriage and significantly fewer divorces, in both cases reversing decades-long trends. An article by Barrett Brown gives more specifics.
Indeed, there appears to be no evidence from anywhere showing same-sex marriage having a negative affect on traditional marriage, and even those who claim that it does have a hard time explaining how. Most often they resort to vague references to "changing the definition of marriage."
Even if that were true, how exactly would it harm traditional marriage? If someone redefined "refrigeration" to mean "marriage," would that damage traditional refrigerators? Would it have any affect on them at all? And if "same-sex marriage" requires redefining marriage, why is it that we understand what it means without needing to have it explained (whereas "same-sex refrigeration" would be a mystery)?
Some contend that marriage exists to provide a nurturing environment for children, and since same-sex couples can't procreate, they shouldn't be able to marry. If the people saying this were serious, they'd say the same of traditional couples unable to have to bear children. Even more to the point, same-sex couples can and do raise children, often the offspring of one member of the couple. There's no evidence that same-sex parents do a worse job than opposite-sex parents, and it's hard to see how denying them the right to marry benefits their children.
Recall that in 1967's Loving v Virginia (a remarkably apt name, that), the Supreme Court unanimously overturned Virginia's law against mixed-race marriage, holding, "The freedom to marry has long been recognized as one of the vital personal rights essential to the orderly pursuit of happiness by free men," and calling marriage "one of the basic civil rights."
That's a real defense of marriage.