Recent decisions by former Secretary of State Hillary Clinton and Sen. Rob Portman, R-Ohio, to come out in favor of gay marriage highlight the rapidly changing nature of views on this issue. In 2012, for example, Pew Research became the latest to find that more Americans favor than oppose allowing gays and lesbians to wed.
Many believe this shift can be attributed to the increasing number of individuals who say they personally know someone who is gay. Certainly, Portman cites his son Will, who came out to his parents in 2011, as the primary reason for his change of heart.
Television and pop culture, too, have received some of the credit. On Friday, Washington Post blogger Chris Cillizza quoted a media consultant saying the proliferation of mainstream TV shows depicting gay people has made the public more open to homosexuality.
But looking at polling trends over the past few decades reveals another possible explanation: Efforts by gay-rights opponents to maintain the "traditional" definition of marriage may actually have caused millions of Americans to question whether such a position is morally tenable.
As this chart from Gallup shows, prior to the 2008 election, the biggest change on the question of whether marriages between same-sex couples should be recognized by the law occurred during the late 1990s. Over the course of about three years, support for recognizing gay marriages rose 14 points (from 27 percent saying they should be valid and 68 percent saying they should not in 1996, to 35 percent saying they should be valid and 62 percent saying they should not in 1999). What happened during that period to cause such a jump?
For one thing, the Defense of Marriage Act was signed into law in September 1996. Also that year, as many as ten states passed legislation refusing to allow or recognize same-sex unions. Never before had the country so forcefully voiced the belief that gay men and women ought to be legally excluded from the institution of marriage. Not long after, the Gallup numbers show, that opposition began to decline.
A similar phenomenon occurred following the 2008 election. In November of that year, voters in three states—Arizona, California and Florida—enacted measures barring same-sex couples from enjoying the right to legal unions.
That May, gay-marriage opponents outnumbered gay-marriage supporters by 17 points. By May 2011, supporters represented an outright majority—a 25-point swing in just two years. During the 2012 election, no states voted to ban gay marriage, and three—Maine, Maryland and Washington—voted to allow it.
Public opinion trends suggest that legislative wins in 1996 and 2008 may have done more harm than good to the cause of "traditional marriage." Today, marriage equality for all is virtually a foregone conclusion. It seems the act of formally codifying the belief that gay couples shouldn't be allowed to wed caused many Americans to rethink their position.
Perhaps the arc of the moral universe is not so long after all.