Bill Jones is a 45-year-old gay Republican from Dallas. For the first time in his life, he's considering voting for a Democrat in a presidential election. Jones still doesn't agree with the Democrats on fiscal policy or the size of government, but last week his priorities shifted.

On May 9 President Barack Obama told ABC's Robin Roberts that he believed same-sex couples "should be able to get married." A day later, likely Republican nominee Mitt Romney affirmed his opposition to same-sex marriages and civil unions.

"It stopped me dead in my tracks because it removed the one rationalization I always had," Jones said. He never thought he would be casting a vote based on a candidate's views on gay rights, but in past presidential elections, neither candidate supported same-sex marriage. "I was always able to say, Well if both sides aren't really going to do anything, I'm going to vote for the side that supports free markets and private property rights."

Much attention has been paid to how Obama's announcement on same-sex marriage will affect the election. There is a wide range of opinion about whether Democrats, Republicans or independents will likely be swayed. But little attention has been paid to the reaction of a small group of voters: gay Republicans.

Bill White, the prominent former president of the Intrepid Museum, recently asked that his donation to the Romney campaign be returned as a result of Obama's shift on marriage. Will more gay Romney supporters follow suit?

In a CNN exit poll from the midterm 2010 congressional elections, 29 percent of those who self-identified as gay, lesbian or bisexual said they had voted Republican. For this group of voters, the 2012 election presents the sharpest contrast between candidates' views on gay rights since Bill Clinton's pledge in 1992 to lift the ban on gays serving in the military and George H.W. Bush's opposition to such a move.

"I don't think it's ever been this stark," said Chris England, a gay Republican from Las Vegas who says he can't bring himself to vote for either candidate. "You want to vote for a candidate that has the most things that you like, but I can't do that if that candidate sees me as less of a citizen."

Of course, not all gay Republicans are jumping ship. R. Clarke Cooper, executive director of the Log Cabin Republicans, the only national GOP organization concerned with gay, lesbian, bisexual and transgender rights, said that after Obama's announcement he had heard from many members who still plan to vote for Romney and that other issues, such as national security, health care and economic policy, still trump marriage.

"For those people, the marriage debate is cacophony in the background," Cooper said, adding that Romney has been supportive of some issues important to his members, such as state anti-discrimination laws protecting gay citizens. The Log Cabin Republicans won't decide whether to endorse Romney until its membership votes in August, but Cooper said he didn't think last week was necessarily a turning point for his group.

"We already knew that the Log Cabin Republicans and Mr. Romney were on opposite ends of this issue, so it wasn't like last week was such a shock," Cooper said. "There might be a reduction of enthusiasm, but it's hard to measure that now."

Many experts think that the issue won't have a huge impact on the election's outcome because people motivated by this issue are already hardline Democrats or Republicans. But this fall gay Republicans could prove the exception.

"The really big question that the Republicans must struggle with more and more now is this, What do they want gay people to do?" said Andrew Koppelman, a political science professor at Northwestern University. "Their answer seems to be, Well we want you to have this second-class status in society, where you have to accept that you and your family are seriously going to be hurt by policies we support, and support us nonetheless."

Two days after the president's announcement, a former pollster for George W. Bush's 2004 re-election campaign sent a memo to Republican operatives urging them to shift how the GOP discusses same-sex marriage. Jan van Lohuizen noted that support for same-sex marriage is shifting "at an accelerated rate with no sign of slowing down."

His memo also states an increase in support is emerging among all partisan groups and age ranges. Van Lohuizen offered recommended statements for Republicans trying to appeal to voters: "People who believe in equality under the law as a fundamental principle, as I do, will agree that this principle extends to gay and lesbian couples; gay and lesbian couples should not face discrimination and their relationship should be protected under the law. People who disagree on the fundamental nature of marriage can agree, at the same time, that gays and lesbians should receive essential rights and protections such as hospital visitation, adoption rights, and health and death benefits."

Some Republicans have already moved toward offering greater support for LGBT Americans. But in the presidential election, the line has been drawn.

Bill Jones, the Texan conservative, has spent his entire adult life trying to balance his gay identity with his Republican politics. In college, he was an active member of the gay and lesbian student association while serving as vice president of the Young Republicans. He kept his dual participation totally secret from both groups.

"I used to be very good at compartmentalizing," Jones said. "But it does make a difference now that Obama has said what he's said. I can't just pretend it didn't happen."