Fueled by a landmark Supreme Court ruling and other legal developments, an emerging national debate over gay marriage has thrust both President Bush and his Democratic challengers onto treacherous political terrain.
Bush and the major Democratic presidential candidates agree on a central point: They do not support granting same-sex couples the right to marry in the United States.
The Republican incumbent and most of the Democratic candidates also agree on something else: They would rather change the subject.
That may prove impossible. Pending court cases in Massachusetts and New Jersey are testing whether same-sex marriage should be legal in those states. Gay and lesbian couples have been trekking northward to Canada to wed since same-sex marriages became legal in that country last month. They are now returning to their homes in the United States, and many may soon be pressing for U.S. recognition of their Canadian status.
Legislation to expand rights and responsibilities for same-sex domestic partners is advancing in California, and major companies -- such as Wal-Mart -- are announcing nondiscrimination policies to protect gay employees.
Above all, the U.S. Supreme Court ruling last week that struck down state anti-sodomy laws is continuing to reverberate, intensifying the debate over same-sex marriages.
"This issue creates a challenge for both parties," said Whit Ayres, a Republican pollster.
He added that the court ruling, which came in a Texas case, "raised the prominence of homosexual marriage on the political agenda and will force some politicians to address the issue who would otherwise have chosen to remain silent."
Bush is feeling some heat from social conservatives, who are pushing for a constitutional amendment to ban gay marriage.
Asked Wednesday whether he would support that measure -- backed by Senate Majority Leader Bill Frist (R-Tenn.) -- Bush told reporters: "I don't know if it's necessary yet. Let's let the lawyers look at the full ramifications of the recent Supreme Court hearing. What I do support is the notion that marriage is between a man and a woman."
Frist, when asked on a Sunday talk show if he supported the amendment, said: "I absolutely do. Of course, I do."
Bush's caution over the proposed amendment, and Frist's enthusiasm for it, reflected the political tensions it causes among Republicans.
Social conservatives are worried that gay marriage could soon become legal somewhere in the United States, perhaps as early as this summer in Massachusetts, pending the outcome of the lawsuit in that state's highest court.
But some GOP centrists are quietly sympathetic to the idea, and others are more vocal about supporting gay civil rights in other ways.
A group known as the Republican Unity Coalition, which includes former President Ford as an advisor, supported the gay plaintiffs in the Supreme Court case and seeks to make sexual orientation "a nonissue in the Republican Party."
In addition, pragmatists are loath to alienate any sector of the electorate that might otherwise tilt toward Bush.
The issue is no less difficult for Democrats. Although the party's nine contenders for the presidential nomination are, on the whole, proponents of gay rights, they are mindful that President Clinton in 1996 signed into law the Defense of Marriage Act.
That law, which gay-rights organizations strenuously opposed, established a federal definition of marriage as limited to the union of a man and a woman. It also allowed states to refuse to recognize same-sex marriages should they become legal in any other jurisdiction of the United States.
Of the five Democratic candidates in the current field who were then in Congress, three voted for the measure: Rep. Richard A. Gephardt of Missouri and Sens. Joe Lieberman of Connecticut and Bob Graham of Florida. Sen. John F. Kerry of Massachusetts opposed it, but said at the time he also was against same-sex marriage.
Carol Moseley Braun, then a senator from Illinois, voted against the legislation and has endorsed gay marriage. But Moseley Braun and the two other Democratic presidential candidates who back gay marriage -- Rep. Dennis Kucinich of Ohio and the Rev. Al Sharpton of New York -- are generally considered the longest shots in the field.
The two other Democratic candidates, Sen. John Edwards of North Carolina and former Vermont Gov. Howard Dean, have said they do not support gay marriage.
Dean, however, opposes the 1996 federal law. He also signed into law in 2000 a Vermont measure that established "civil unions" as an alternative to marriage for gay couples.
That law -- the first of its kind -- confers on Vermonters more than 300 benefits traditionally enjoyed by married couples, such as inheritance rights. But such unions are not recognized by other states or the federal government.
In a statement on his Web site, Dean said he would relish a debate with Bush over the Vermont law and the federal law. "I can't wait to ask the president of the United States why he doesn't support equal rights," Dean said.
Several other Democratic candidates have criticized Bush's record on gay rights. All have endorsed federal legislation to ban discrimination in the workplace on the basis of sexual orientation. Most want to revise the military's "don't ask, don't tell" policy that requires gay and lesbian soldiers to keep their orientation a secret.
But few Democratic strategists see an assault on the Defense of Marriage Act as a step toward victory in 2004. Three dozen states have versions of the federal law. California voters passed one in March 2000, with their landslide approval of Proposition 22.
When Democratic contenders roundly praised the Supreme Court ruling last week, conspicuously absent from many comments was the issue of gay marriage.
Lieberman's statement was typical: "The court," he said, "moved us a step closer to giving gays and lesbians a full, fair place in our society." But he did not say what the next step should be. A campaign spokesman declined Wednesday to elaborate.
If candidates are reticent on the subject, activists are not.
The National Gay and Lesbian Task Force in May published a study declaring that as a group, the Democratic candidates were more supportive of equal rights for gays than any previous batch of White House aspirants.
But Sean Cahill, who edited the report, said gay and lesbian voters -- an influential force within the party -- should demand more.
"We want people to use this and go to Howard Dean in a forum or John Kerry and say, 'Why don't you support marriage?' " Cahill said. "Look Joe Lieberman in the eye, and say, 'Why are you not with me on this?' "
Similarly, many social conservatives have grown restless at what they view as Bush's muted response on gay rights' issues.
They were disappointed that the administration did not support the Texas anti-sodomy law as the Supreme Court considered the case, even though Bush as governor backed the law.
They wanted the White House to more strongly support Sen. Rick Santorum (R-Pa.) when he became embroiled in controversy in April after an interview in which he linked consensual gay sex to adultery, bigamy and incest.
Now they want Bush and his administration to be more outspoken in opposing gay marriage.
"Try as they might, they're not going to be able to avoid the issue," said Ken Connor, president of the Family Research Council.