WASHINGTON — A slim majority of Americans now back gay marriage, according to a new Washington Post-ABC News poll.

The results underscore the nation’s more tolerant views on homosexuals, and parallel recent legal and legislative victories for gay rights advocates.

Five years ago, at 36 percent, support for gay marriage barely topped a third of all Americans. Now, 53 percent say gay marriage should be legal, marking the first time in Post-ABC polling that a majority has said so.

“This is very consistent with a lot of other polling data we’ve seen and the general momentum we’ve seen over the past year and a half,” said Evan Wolfson, president of Freedom to Marry, a leading pro-gay-marriage group based in New York.                

Opponents of same-sex marriage took issue with the poll, which asks respondents: “Do you think it should be legal or illegal for gay and lesbian couples to get married?” Brian Brown, president of the National Organization for Marriage, said the term “illegal” could be inferred to mean that violators could be imprisoned, which most Americans would consider harsh.

Brown, whose organization is a prominent anti-gay-marriage group, noted that all 31 states that have put same-sex marriage on the ballot voted to ban it. “The only poll that counts is a free and fair vote on the part of the people,” he said. “We’ve seen these biased polls time and time again – right before votes in which same-sex marriage is rejected.”