When it comes to attending a gay wedding, not all presidential aspirants say, I do.
It sounded like a simple, if unusual, question to ask a potential leader of the free world: Would you attend a gay wedding?
But it has become a new kind of conservative litmus test for potential presidential candidates on a key social issue.
Marco Rubio, once seen as front-runner, has some catching up to do
Most of the Republican hopefuls stand squarely in the traditional camp of defining marriage as between a man and a woman, and they oppose efforts, like the one looming before the Supreme Court, to legalize gay marriage nationwide.
But would attending the gay wedding of a friend or family member be a bridge too far?
The question was first posed this week to Sen. Marco Rubio, the Florida Republican, after the 43-year-old launched his presidential campaign as the party's face of a new generation of leadership.
"If it's somebody in my life that I care for, of course I would," Rubio told Fusion's Jorge Ramos.
"I'm not going to hurt them simply because I disagree with a choice they've made," he said. "You respect that because you love them."
Not so fast, said former Republican Sen. Rick Santorum.
The conservative Catholic, who expects to use family values to attract a wide following if he jumps into the race, drew the line at celebrating gay marriages.
"No, I would not," Santorum told radio host Hugh Hewitt. "As a person of my faith, that would be something that would be a violation of my faith. I would love them and support them, but I would not participate in that ceremony."
Uproar over Indiana religious freedom law shows shift in gay rights fight
Sen. Ted Cruz (R-Texas) seemed to wriggle out of the question, saying he had not yet been invited to any gay weddings so had not considered whether he would attend such a bash.
Jeb Bush, the former Florida governor, also does not appear to have yet faced the question, though he joined most of the other Republican hopefuls in siding with a recent Indiana measure that gay-rights advocates feared would allow businesses to refuse services to gays on religious grounds.
"This is simply allowing people of faith space to express their beliefs," Bush said before the Indiana legislature -- facing pressure from business and civil rights groups -- passed another law to clarify that such discrimination would not be allowed.
Public attitudes toward gay marriage have been among the most rapidly changing of any social issue as polls show voters have essentially flipped in recent years to support it.
The swift and unexpected shift has forced Democratic and Republican candidates to scramble to adjust -- or evolve, as many say -- with the times.
President Obama acknowledged his own evolution on the issue, and a spokeswoman for the Democratic front-runner, Hillary Clinton, said Thursday she would like to see the Supreme Court clear the way for same-sex couples to marry.
The high court will be asked later this month to strike down the remaining state bans on gay marriage.
The Human Rights Campaign, the large LGBT advocacy organization, welcomed Clinton's belief that "all "committed and loving couples should be able to marry," said Fred Sainz, the vice president of communications. “It’s unfortunate that all of the Republican candidates have chosen to be on the wrong side of history."