Updated

Gay marriage (search) is emerging as a big enough issue in several states to influence races both for Congress and the presidency.

Ballot initiatives on banning same-sex marriages are expected to propel social conservatives to the polls in 11 states, including four presidential battlegrounds: Arkansas, Ohio, Michigan and Oregon.

The topic also is a prominent issue in Oklahoma, South Dakota and North and South Carolina, all states with close Senate contests.

An independent group has run an ad in South Dakota, where Senate Democratic leader Tom Daschle (search) is in a tight race, saying Daschle "refuses to protect marriage; he would let liberal activist judges redefine it."

In Arkansas, GOP state Sen. Jim Holt has made homosexual marriage the central theme of his longshot campaign against Democratic Sen. Blanche Lincoln. It's not the only issue, he said, "but it is the most important issue, I believe, in America."

President Bush (search), in the final presidential debate, reiterated his support for a constitutional amendment banning gay marriage, saying he was concerned that, otherwise, "activist judges" would rewrite the definition of marriage.

Democratic presidential candidate John Kerry expressed the view of many in his party after a narrow ruling by the supreme court in his home state of Massachusetts a year ago legalized same-sex marriage gave Republicans a new issue to activate their base.

Kerry said he supports the right of homosexuals to form civil unions. He opposes same-sex marriage, but also is against a constitutional amendment that would ban it. States should determine marriage laws, he said.

The nuances of that stance are often lost in 30-second TV ads and campaign literature suggesting that Democrats, by opposing a constitutional amendment, are clearing a path for gay marriage.

That was the message in a Republican National Committee mailer sent to voters in Arkansas and West Virginia, with a picture of a man placing a ring on the hand of another man. It said a failure to vote would open the way for liberals to ban the Bible and allow same-sex marriage.

"The people who put this out (are) taking West Virginians to be gullible, ignorant fools," Sen. Robert Byrd, D-W.Va., told an interfaith group in his state.

But Roberta Combs, president of the Christian Coalition of America, said defense of marriage transcends even abortion as a social issue this year because it concerns a spectrum of voters well beyond social conservatives. "Christians are going to turn out more than they did last time," she predicted.

Peter Sprigg, senior director of policy studies at the Family Research Council, said his group also hopes "there will be a strong turnout of people with strong family values."

Sprigg stressed that the referendums in the 11 states derived from court rulings and were not "cooked up as a tool to help re-elect the president."

Cheryl Jacques, president of the Human Rights Campaign, a gay and lesbian support group, saw it differently, saying it was "no coincidence" that in states where races are tight, "we're seeing the ramping up of the issue with billboards and flyers."

The Family Research Council and other conservative groups are putting out scorecards to inform voters how their representatives and senators voted on proposed constitutional amendments to ban gay marriage that were rejected in both the House and Senate this year.

In North Dakota, Mike Liffrig, in an uphill race against Democratic Sen. Byron Dorgan, attacks Dorgan over his constitutional amendment vote using an ad showing two tuxedo-wearing men moving in for a kiss.

In North Carolina, Rep. Richard Burr, in a tight Senate race with Clinton White House chief of staff Erskine Bowles, cited Bowles' opposition to a constitutional amendment in an ad that said "it's a shame Erskine Bowles doesn't have the courage to stand up for traditional marriage."

Gay rights in general has cropped up in several other close senatorial races.

Former Rep. Tom Coburn, the Republican candidate in Oklahoma, sparked a controversy when he warned of "rampant" lesbianism in some Oklahoma schools. GOP Rep. Jim DeMint, running for the Senate in South Carolina, caused a stir by saying that openly gay people and unwed, pregnant women should be barred from teaching in public schools.

Gay rights groups say Bush and others could be making a mistake by courting his conservative base and ignoring moderate swing voters.

Patrick Guerriero, head of the gay Log Cabin Republicans, a group that has withheld its endorsement of Bush over the marriage issue, told the Republican National Committee that "appealing to people's anti-gay animus as a campaign strategy betrays the (inclusive) legacy of President Ronald Reagan."

In using a divisive issue such as gay marriage, said the Human Rights Campaign's Jacques, "you don't know who you are offending. There's no way of knowing what the backlash is."