Almost three in four Americans believe it’s inevitable that same-sex marriage will be legalized in the United States, including a majority of people who most ardently oppose it, according to a new poll released Thursday.

In the Pew Research Center poll conducted early last month, 72 percent called same-sex marriage inevitable. Among gay-marriage supporters, 85 percent said it was bound to happen. Among opponents of legalizing same-sex marriage, 59 percent said they expect it nevertheless. That was much higher than the 51 percent who told Pew they support legalizing gay marriage, while 42 percent opposed it.

The expectation that gay nuptials will be legal everywhere in the United States ran high even among Republicans, people 65 and older and white evangelical Protestants — all groups that overwhelmingly reject gay marriage.

The poll seemed to capture rapidly shifting attitudes about marriage equality, even as the Supreme Court is poised to rule by the end of this month on two cases involving the issue. poll conducted by LifeWay Research

Opponents of same-sex marriage said that media coverage of several recent polls posing the inevitability question has helped convince people that same-sex marriage cannot be stopped.

Brian Brown, president of the National Organization for Marriage, called the poll results “overinflated.”

“Even in this poll, you still have a significant group of Americans who don’t think it’s inevitable and who are willing to stand up and fight, even though all they hear constantly is that it’s inevitable,” he said. “The real question is, do they support same-sex marriage? Given the chance to vote on this, in the overwhelming majority of states people voted what they know is true, that marriage is between a man and a woman.”

But supporters of same-sex marriage said the Pew poll reflects a growing acceptance of such unions and a shift in attitudes, as more Americans have gay friends, relatives and co-workers. Pew found that nearly nine out of 10 Americans know someone who is gay, and half said a close friend or relative is gay. The poll said people with gay and lesbian acquaintances are more likely to support same-sex marriage than people who say they don’t know anyone who is gay.

“It’s clear that is not a wedge issue anymore,” said Fred Sainz, a spokesman for the Human Rights Campaign, which advocates changing laws to recognize same-sex
marriages. “Not only are Americans supportive of marriage equality, even those who are opposed to it view it as inevitable. That’s a proxy for their eventual support, in my opinion.”

Sainz said opposition to gay marriage often crumbles when people learn how many people they live and work among are gay.

“When you get to know them, you quickly find the myths propagated against gay people by our opponents are not true,” he said. “My goal is to get to the point where gay people are thought to be as dull and boring as everyone else, because we are.”

Noting that the 2010 Census found only one county in the country, in Mississippi, that did not count a gay couple living together and identifying themselves as partners, Sainz added: “In the 44 years since the Stonewall riots, our movement has been accelerated light-years by people coming out of the closet and sharing their lives with others. ”

The poll identified a strong link between religious beliefs and opposition to gay marriage. More than half the people who told Pew that homosexuality should be discouraged in society cited moral and religious objections. Only one in 10 cited other reasons, such as concern for children or a belief that homosexuality is “just wrong.” By a wide margin, people who attend religious services at least weekly called homosexual behavior a sin, Pew said.

Peter Sprigg, a senior fellow for policy studies at the Family Research Council, predicted the only way marriage will be redefined is by Supreme Court order.

“Barring a shockingly radical decision by the Supreme Court, which few serious observers expect after the oral arguments, the debate over marriage is likely to continue state by state for many years to come,” he said.