WASHINGTON — As a political, legal and social issue, same-sex marriage seems to be now where interracial marriage was about 50 years ago.
A large majority of the public and most politicians say they oppose gay marriage. Some church leaders say it violates natural law and the Scriptures. A movement growing in political importance is pressing for equal rights for a minority. And a state high court has thrown out a law prohibiting such marriages. All that was true of interracial marriages shortly after World War II.
Today, interracial marriage has strong public support, and no successful politician or prominent public figure favors outlawing such unions. The question is whether gay marriage is on the same trajectory or is so fundamentally different that it will never be legalized.
Same-sex marriage moved to the forefront last month after Massachusetts' highest court ruled that gay couples have the right to marry under the state's constitution. The court repeatedly cited decisions on interracial marriage a generation ago as precedent.
"Recognizing the right of an individual to marry a person of the same sex," Chief Justice Margaret H. Marshall asserted in her majority opinion, "will not diminish the validity or dignity of opposite-sex marriage, any more than recognizing the right of an individual to marry a person of a different race devalues the marriage of a person who marries someone of her own race."
David J. Garrow, a civil rights historian at Emory University in Atlanta, said he thought gay marriages would soon become as unremarkable a part of American life as marriages between whites and blacks. "I would make the argument that American popular opinion about gay people has been changing even faster than American popular opinion changed with regard to race and interracial marriage," he said.
But another constitutional scholar, Douglas W. Kmiec, a law professor at Pepperdine University in California, disagreed. "People will have to ask themselves, 'Does gender matter?"' he said. "If people seriously reflect on that, they will say it does matter in a way history ultimately proved that race does not matter."
Randall Kennedy, a Harvard Law School professor and the author of a new book, "Interracial Intimacies: Sex, Marriage, Identity, and Adoption," said in an interview that gay marriages would probably follow the same path as interracial unions, but that it might not be soon. "There is still punch to the political forces that don't want gay people to be able to marry," he said.
One big difference, Kennedy said, is that the political drive for equal rights for blacks outpaced legal developments. By the time the Supreme Court declared laws against interracial marriage unconstitutional in 1967, the political fights had been won in the Civil Rights Act of 1964 and the Voting Rights Act of 1965.
But gay marriages are now against the law in every state, and the Massachusetts ruling has generated fierce opposition. Governors and legislators pledged to strengthen their states' laws prohibiting same-sex marriages.
"I don't want to live next door to people who have a same-sex relationship and have children, and have my children playing with them," Emmett C. Burns Jr., a Democratic member of the Maryland House of Delegates, told The Washington Post in calling for such action in his state.
In Washington, some senators and representatives proposed a constitutional amendment specifying that "marriage in the United States shall consist only of the union of a man and a woman." Amendments to put a prohibition against interracial marriage in the Constitution were introduced at least three times from 1871 to 1928 but never reached a vote in Congress, according to the Senate Historical Office.
The political reaction reflected public opinion. A poll last month by the Pew Research Center for the People and the Press showed that 59 percent of those polled said they opposed gay marriages, and only 32 percent favored them. As many blacks as whites, 60 percent, said gay marriage should be against the law, and many blacks said they resented attempts to equate the struggle for racial equality with the battle for gay rights.
"It annoys me because you're comparing apples and oranges," said the Rev. Walter E. Fauntroy, 70, a veteran of the civil rights movement who has been pastor of the New Bethel Baptist Church in Washington for more than 40 years. "If I choose to marry someone of a different race, that's my choice. But don't call a union a marriage if it cannot perform the essential functions of perpetuating the species and socializing the young."
Attitudes on interracial marriage have turned around in a generation. In 1948, when the California Supreme Court threw out the state's law against interracial marriage, 31 of the 48 states had similar laws. In 1968, the year after the Supreme Court legalized interracial marriages, a Gallup Poll found that people, by more than 3-to-1, still disapproved of marriages between whites and blacks. The last Gallup Poll on the topic, in 1997, showed that two-thirds of adults approved of them.
One indication that attitudes on same-sex marriage may be changing in the same way is that people under 30, the Pew poll showed, are evenly divided on whether such marriages should be allowed, while three-fourths of the respondents 65 and older disapprove of them.
William N. Eskridge Jr., a Yale law professor who has written widely on gay rights, said views on same-sex marriage will follow the same path as those on interracial marriage. Blacks, he said, began to mobilize seriously shortly after World War II, and it took decades to achieve their goal. Gays and lesbians, he said, did not mobilize similarly until the 1980s and '90s.
But Gary Bauer, president of American Values, a conservative research institute, said a change of this magnitude would never occur.
"Same-sex marriage," he said, "violates the most basic component of what marriage has been for 3,000 years of Western civilization."