The latest New York Times/CBS News poll has found widespread support for an amendment to the United States Constitution to ban gay marriage. It also found unease about homosexual relations in general, making the issue a potentially divisive one for the Democrats and an opportunity for the Republicans in the 2004 election.

Support for a constitutional amendment extends across a wide swath of the public and includes a majority of people traditionally viewed as supportive of gay rights, including Democrats, women and people who live on the East Coast.

Attitudes on the subject seem to be inextricably linked to how people view marriage itself. For a majority of Americans ? 53 percent ? marriage is largely a religious matter. Seventy-one percent of those people oppose gay marriage. Similarly, 33 percent of Americans say marriage is largely a legal matter and a majority of those people ? 55 percent ? say they support gay marriage.

The most positive feelings toward gay people were registered among respondents under 30, and among those who knew gay people.

The nationwide poll found that 55 percent of Americans favored an amendment to the constitution that would allow marriage only between a man and a woman, while 40 percent opposed the idea.

The findings come after the highest court in Massachusetts ruled 4 to 3 last month that same-sex marriage was permissible under the state's Constitution. That ruling followed a 6-to-3 decision in late June by the United States Supreme Court striking down antisodomy laws.

President Bush had been noncommittal about a constitutional amendment immediately after the Massachusetts ruling, with the administration worried that support for a ban on gay marriage would alienate moderate voters. But last week Mr. Bush for the first time voiced his support, saying, "I will support a constitutional amendment which would honor marriage between a man and a woman, codify that."

The statement signals the White House's increasing confidence that it can exploit the matter in the presidential campaign, both to energize its evangelical supporters and to discredit the eventual Democratic nominee.

Most of the Democratic candidates oppose gay marriage but favor civil unions. Howard Dean, who is leading in the polls for the Democratic nomination, signed a law when he was governor of Vermont allowing civil unions, an action that Republicans have already used to portray him as too liberal for mainstream America.

The court rulings generated extensive publicity and concern, not only about same-sex marriage but also about having the courts set social agendas that have not been approved by the legislative process.

"We have found that the more people focus on it, the less they support it," said the Rev. Lou Sheldon, chairman of the Traditional Values Coalition, which strongly opposes gay marriage and is working actively for a constitutional ban.

The Times/CBS News poll was conducted from Dec. 10 through Dec. 13 in telephone interviews with 1,057 people. It carries a margin of sampling error of plus or minus three percentage points. Responses about gay rights tend to be influenced somewhat by the wording of the questions.

This poll and other surveys show that as the courts have extended legal rights to gays this year, Americans have become increasingly uncomfortable with same-sex relations.

For decades, a majority of Americans have not approved of homosexual relations. That had begun to change, until the Supreme Court ruling in June and the Massachusetts ruling in November. A New York Times/CBS News poll conducted in July found that 54 percent of respondents said homosexual relations should be legal. Only 41 percent of the respondents in the latest poll said they should be legal.

Richard Waters, 71, a retired elementary school teacher in Little Valley, N.Y., and a Republican, said in a follow-up interview to the poll that he strongly supported a constitutional amendment banning gay marriage.

"I think any kind of amendment that says `You shall not' will help," Mr. Waters said. "I just don't think it's right for two men to go parading around in public or for two women to be doing the things they do. It's against God's law. That's right in the Bible that it's wrong."

Theresa Eaton, 49, a financial analyst in Corona, Calif., and also a Republican, agreed.

"I still believe that marriage should be between a man and woman," she said. "If I knew that we had a neighbor who was gay, I would not let my nieces and nephews go close by there. I don't want to accept their lifestyle. It can be acquired and it is not right."

The poll also found that by a 61-34 margin, Americans oppose gay marriage. They are slightly more accepting of civil unions to give gays some of the same legal rights as married couples, with 54 percent opposed to civil unions and 39 percent supportive.

The Massachusetts ruling also gave new impetus in Congress to sponsors of a constitutional amendment to ban gay marriage. An amendment, which would require passage by two-thirds of the House and Senate and three-fourths of the states, would override any state court ruling or legislation.

Representative Marilyn Musgrave, Republican of Colorado, who introduced a constitutional amendment in the House in May, said on Friday that she had 106 co-sponsors. The companion measure in the Senate still has only a handful of supporters.

"Homosexual activists have known that they're not going to get their way in the legislative arena, and they shopped around for activist judges," Ms. Musgrave said. "But if the definition of marriage is to be changed, it should be done by the American people, not four judges in Massachusetts."

Her measure would ban gay marriage. Some gay rights groups say its language is ambiguous on civil unions, but she said on Friday that her intent was to allow states to conduct civil unions but not let them be recognized in other states.

At the moment, only Vermont allows civil unions. In California, a domestic partnership bill giving gay couples limited rights is to go into effect in 2005, but it is under threat of a legal challenge.

Some groups on the religious right who are eager for a constitutional ban on gay marriage said Ms. Musgrave's measure did not go far enough. Mr. Sheldon, for one, said his group was seeking to ban civil unions and domestic partnership laws as well as same-sex marriage.

He said his group and others were lobbying President Bush to assert in his State of the Union address in January that he will also seek a ban on civil unions and domestic partnership laws. The groups are preparing to flood the White House with e-mail messages on the subject.

Jan LaRue, counsel to Concerned Women for America, a conservative religious policy organization, said her group was involved in a public education campaign on "why marriage is important and needs to be protected." She added, "We are part of a broad coalition that is using bumper stickers, newspaper ads, articles on our Web sites and assisting with amicus briefs."

Gay rights groups expressed dismay with the poll results but said they doubted that a constitutional amendment would pass the initial stage through Congress.

"The Republican House leadership is having its own internal fight to determine what to do," said Winnie Stachelberg, political director of the Human Rights Campaign.

"There is no consensus among conservatives, libertarians and Republicans," she said. "Many of them say they don't support marriage for same-sex couples, but to amend the Constitution for social issues is a very bad idea."

The last time the Constitution was amended for social purposes was in 1920, when alcohol was outlawed, but that prohibition was repealed in 1933.

Sanford Levinson, a constitutional expert at the University of Texas Law School in Austin, said it was extremely hard to amend the Constitution. If the ban on gay marriage passed the House and Senate, he said, opponents could stop it by getting the support of one house of the legislature in just 13 states.

Mr. Levinson said President Bush's support was "a free pass" because he probably knows how difficult it would be to get through Congress, let alone through 38 states.

"The idea is for Bush to throw red meat to the Republican right, secure in the knowledge that this is not going to go anywhere," he said. "If it did go anywhere, it would tear the Republican Party apart."

Even in an age when gay couples are routinely portrayed on television and constitute a prosperous demographic that advertisers have been overtly appealing to, the Times/CBS News poll found the country still sharply divided over homosexuality.

Half of the respondents said they viewed homosexual relations between adults as morally wrong. Moreover, an overwhelming majority, 87 percent, said they thought most people would not accept having same-sex couples married within their church, synagogue or place of worship. Sixty percent said they themselves would not accept such unions in their own places of worship.

"I want my children to grow up and be normal people like me and my father and my grandfather was," said Ziad Nimri, 41, a salesman and a Democrat who lives in Spokane, Wash. "I don't want my children to start getting ideas. They see it's out in the open and you see men kissing men on television these days."

Mr. Nimri said he was also worried that if gays were allowed to marry, they would get other rights too, like tax benefits. "Because they're a minority, they're going to start actually giving them more privileges than normal people would have," he said. "Minorities always tend to get more than your average person does."

One of the few people interviewed who was not opposed to legally recognized same-sex marriages was Cliff Martin, 47, an unemployed Democrat in Gainesville, Fla. "I think gays should be allowed to marry because it's not something that threatens other people," he said.

Correction : December 24, 2003

Because of an editing error, an article last Wednesday about an ABC television interview in which President Bush discussed a constitutional amendment on same-sex marriage quoted him incompletely. (The quotation was also incomplete in a front-page article on Sunday about a New York Times/CBS News poll showing widespread support for an amendment to ban same-sex marriage.) What the president said was, ''If necessary, I will support a constitutional amendment which would honor marriage between a man and a woman, codify that.'' The Wednesday article, while omitting the words ''if necessary'' from the quotation, did specify them in a separate paragraph.