Jan van Lohuizen of Voter Consumer Research (pollster for George W. Bush) and Joel Benenson of Benenson Strategy Group (pollster for Barack Obama) conducted a study on the changing American attitudes toward same-sex marriage. They studied the exit polls from the 2012 election. In their report released on March 7th of this year, they concluded that the opponents of same-sex marriage are becoming "increasingly isolated within narrow demographic groups while a much broader and more diverse majority are ready to let same-sex couples marry."
While the support for same-sex marriage in the general public is only about 53% right now (with opposition to DOMA even higher at 59%), about 83% of the general public believes that it will be legal nationally in 5 to 10 years. And while most Republicans still oppose it, that opposition is dwindling, as a majority of Republicans under 30 years-old support the legalization of same-sex marriage (51% to 46%).
Here are the remaining groups still opposed to that legalization of same-sex marriage:
Republicans opposing teabaggers...............47% to 52%
Republicans neutral to teabaggers...............34% to 62%
Republicans supporting tea baggers...............13% to 84%
White non-college graduates...............40% to 56%
White evangelical christians...............24% to 73%
Voters over age 65...............37% to 58%
And here are the groups supporting legalization of same-sex marriage:
Voters under age 65...............52% to 44%
White non-evangelical protestants...............54% to 43%
White catholics...............53% to 43%
Hispanic catholics...............54% to 35%
African-American non-evangelical...............65% to 31%
Jewish...............78% to 21%
Non-white non-college graduates...............54% to 38%
White college graduates...............56% to 41%
Non-white college graduates...............58% to 35%
Democrats...............68% to 27%
Independents...............54% to 40%
Republicans under age 30...............51% to 46%
Whites under age 65...............50% to 46%
African-Americans under age 65...............51% to 40%
Hispanics under age 65...............60% to 31%
All voters except white evangelicals...............58% to 36%
Benenson and van Lohuizen then reach the following conclusion (which I wholeheartedly agree with):
Given all the above data, and other data and trends we've seen, it is clear that opponents of the freedom to marry are both on the wrong side of a majority of Americans and on the wrong side of history.