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Same-sex marriage advocates protest outside the county clerk's office in San Francisco on Feb. 14.
When Ohio Republican Sen. Rob Portman recently reversed his stance on gay marriage after his son came out as gay, he joined a tidal wave of Americans who have altered their views on the subject.
This dramatic change forms the backdrop to two Supreme Court cases this week about the constitutionality of same-sex marriage. Support has reverberated at the highest level: The White House has urged the high court to come down in favor of gay rights, and President Obama has reversed his own stance on the issue.
"There's just been a real huge sea change in how people view gay marriage," says Dawn Michelle Baunach, a sociologist at Georgia State University who has tracked attitudes toward same-sex marriage over the past two decades.
"In 1988, we had 72 percent of people who said they disapproved of gay marriage, and only 13 percent approved. But by 2010, we had cut disapproval almost in half, and approval has quadrupled," she says.
The latest public opinion surveys show an even greater jump. About one-third of Americans now oppose gay marriage, while some 58 percent support it.
Baunach notes that there has been an acceleration in how quickly opinions about same-sex marriage changed after 2008. She says that for many Americans, gay marriage was no longer an abstract issue, but a personal issue that touches the life of someone they know.
"They can think about it on a more personal level," she says. "Instead of just reacting on a more, 'Oh, that doesn't seem right' [level], they [think], 'Well, you know, Jane is a great person, I like her, I've met her girlfriend and it seems perfectly reasonable that they should be able to get married.' "
Baunach's research suggests that the dramatic shift in attitudes is not because of what sociologists would call "generational change." It has long been known that older people are more likely than younger people to oppose gay marriage. But Baunach says the national change was less about older Americans dying and leaving behind a more liberal America, and more about the fact that many Americans who once opposed gay marriage have changed their minds or softened their opposition.
Support for gay marriage two decades ago was largely restricted to secular and highly educated urban dwellers. Increasingly, though, Baunach says, rural people, those with less education, and even religious people were showing signs of support. Opposition among Republicans, evangelicals and African-Americans, however, remains strong.
Another explanation for the change is that the institution of marriage among heterosexuals has been undergoing a substantial transition, Baunach says.
Many Americans are redefining their intimate relationships in nontraditional ways, she says. Revised views on gay marriage could be related to steadily changing perspectives toward sexuality over the past several decades.
Yet another explanation might have to do with the way the issue of gay rights has come to be framed as an individual rights issue, Baunach says. Other research suggests that Americans resonate with messages that highlight the importance of individual liberty.
Baunach predicts that if current trends continue, the country will soon look like a mirror image of itself from a quarter-century ago: A minority of Americans may be left opposing same-sex marriage, while an overwhelming majority support it.
But she also notes that such a trend is hardly irreversible: While minorities of Americans appear to be fervently for and fervently against gay marriage — and can reliably be expected to stick to their views — a substantial bloc of Americans appear to have views that are open to persuasion.