Poll: Rising U.S. Support for Social Issues, Such as Gay Marriage

The poll showed just how much of the movement is occuring among younger voters. Support for gay marriage has grown somewhat among voters over age 65, from 15 percent to 28 percent, but six in 10 remain strongly opposed. Among those under 35, though, two-thirds support it, up from 53 percent in 2006, and nearly half support it strongly. More broadly, Republicans face a sharp partisan gap among those under 35, only 17 percent identified as Republican, with 43 percent calling themselves independent and 36 percent Democrats. Across all age groups, 21 percent identified as Republicans in the poll, the lowest level in Post-ABC polling since 1983.

Maia Duncan, a 23-year-old college student in Santa Cruz, Calif., who considers herself a moderate Democrat, said she saw the issue as one of basic fairness. "I was raised to be open-minded," she said. "It's different generations," she said. "This generation was raised by a different era. It's different times."

Even among some who oppose gay marriage, the issue may not be much of a motivator. Joe Parmeley, 43, a moderate Republican who was raised Catholic and owns an auto repair shop in Maricopa County, Ariz., voted for a successful constitutional amendment to ban gay marriage in Arizona but says he does not see any problem with other states legalizing it. "Whatever the law of the people is what should stand," he said. "If it would've passed [in Arizona] then fine, gay marriage is legal . . . It should come down to the people in that state deciding on their own."

More than half of those who live in states where gay marriages are not legal -- 53 percent -- said that their state should recognize gay marriages that have been legally conducted in other states, 43 percent said their state should not recognize those marriages.

Another issue that has served as a Republican rallying cry, immigration reform, may become more difficult terrain for them. While 74 percent said that the government is not doing enough to keep illegal immigrants from entering the country, including majorities across party and demographic lines, public sentiment has shifted away from that view since its peak in 2007 among most groups outside the Republican core. At the same time, a growing slice of the population -- including Republicans -- support the broad outlines of a plan giving illegal immigrants "the right to live here legally if they pay a fine and meet other requirements." Six in 10 overall (61 percent) would support such a plan, up from 52 percent in June 2007. Support is highest among younger voters, and independents have gone from being roughly split on the plan to being mostly in favor of it, 59 percent now support it.

Respondents were near split on another issue that until recently was deemed untouchable in many parts of the coutry -- marijuana legalization. Forty-six percent of all respondents said they supported legalizing "possession of small amounts for personal use," with rates of support higher among men, among younger voters and among independents, a majority of whom supported legalization.

One issue in the survey where public opinion has drifted in the conservative direction is gun control, where Obama and other Democrats have studiously avoided pushing for major reforms. Fifty-one percent of respondents said they favored stricter gun laws, down 10 points from 2006.

And fewer now say stronger laws would reduce the amount of violent crime in the U.S., and six in 10 said enforcing current gun laws is a better way to diminish crime than passing harsher laws.

This shift was notable given that the poll took place after a string of mass shootings around the country. And it occurred across ideological lines, with a striking shift among moderate voters -- 53 percent said they favored stricter gun laws, down from 71 percent in 2000. Opposition to stricter laws was highest in the West.

Duncan, the California student, is representative of the ideological mix in the survey. Though conficted about immigration, she supports reform to let some illegal immigrants stay. She supports legalizing marijuana, "as long as it's taxed." But she is against stricter gun control. Her family owns a gun and she sees no need for reforms. "Gun control laws are getting insane," she said. "I understand the point is to make people safer, but the laws are there and do work. They should be policing people more, with heavier punishment for people who are breaking the law."

Polling director Jon Cohen contributed to this article.