Editor's note: This article is the third in a series on issues in the 2004 presidential campaign.

Gay marriage is a wedge issue that many voters care about, and for some heading to the polls on Nov. 2, it is the key issue. If the election is decided by a razor-thin margin, the candidates' stark differences on gay marriage (search) could be the reason for victory or defeat.

President Bush wants a constitutional amendment barring gay marriage; John Kerry wants to leave the decision up to the states. Bush's position has helped solidify his position among Christian conservatives, and his political operatives say they hope it helps boost turnout among this voting bloc. But gay Republicans and others in the community vow Bush will lose a significant number of the gay votes he received in 2000.

Bush's reasons for coming out so strongly against gay marriage are clear, say gay activists. "The hope that it will energize the far right base. [But] it's very unclear whether that strategy will actually work," said Matt Foreman, executive director of the National Gay and Lesbian Task Force (search), which describes itself as the oldest national organization working to eliminate prejudice against lesbian, gay, bisexual and transgender people.

"When you poll the American public about what are the most important issues facing the country, same-sex marriage is at the bottom of the list. It's just not a burning issue for most people," Foreman said.

Conservatives say they have been happy about Bush's leadership on this issue and his stance favors the president in the election.

"He is clearly seen as a candidate that is championing marriage," said Tony Perkins, president of the Family Research Council (search).

Many homosexuals are not happy with John Kerry for his unwillingness to support gay marriage, but see him as a better champion of their cause. Kerry has said he would oppose a consitutional amendment to ban gay marriage, and would leave the decision up to the states. Gay groups praise his positions on other issues they are concerned about like anti-discrimination and hate crime legislation, and say while the Massachusetts senator is far from ideal, he will capture their vote because of the aggressively anti-gay stance of the president.

"I think most of us are disappointed about John Kerry and John Edwards' stand on this issue. At the same time, there are a lot of important issues in addition to marriage," such as service in the military, domestic partnership, HIV prevention and others, Foreman said.

"Kerry and Edwards are not there on marriage, but they are there on all those other issues. ... On balance we wish they would be better on marriage equality but there is just no comparing on a factual level the position of the two presidential candidates," Foreman added.

In 2000, 1 million gay Americans voted for Bush. But that number could drop this year. The board of directors of the Log Cabin Republicans (search), the GOP's largest gay group, voted 22 to 2 last month to withhold its endorsement for Bush, calling him "disloyal" to the homosexuals who supported his candidacy in 2000. Log Cabin Republicans endorsed Bob Dole in 1996 and Bush in 2000.

"There is a battle for the heart and soul of the Republican Party, and that fight is bigger than one platform, one convention, or even one president," Log Cabin Republicans Executive Director Patrick Guerriero said in a statement.

In a Los Angeles Times editorial following the vote, Guerriero charged that Bush's stance is part of a calculation by presidential adviser Karl Rove that "4 million evangelicals stayed home in 2000. As a result, the 2004 campaign has focused on energizing the far right while ignoring mainstream Republicans."

Perkins said if the issue is a true motivator for voters, Bush has nothing but gains to make.

"When you factor in that homosexuals make up 3 percent of the population and evangelicals a little over a quarter," the issue will benefit Bush more than Kerry, he said. "This is an issue that has been brewing for some time. This is an issue that will have significant implications for the presidential election."

"I think it's helped Bush energize his base," added Terry Madonna, director of Franklin & Marshall College's Center for Politics and Public Affairs (search).

However, Madonna was still wary about the overall impact of this wedge issue. "This is not an election that will be largely won or lost on the cultural issues," he said. Instead, the most important subjects would be homeland security, war and the economy.

"At this point I do not see these [cultural] issues as defining the nature of the campaign. Is it possible they could influence some people at the margins and maybe because the election is so close make the difference? Yeah, it's possible."