It was so casual, the way Marco Rubio slipped same-sex marriage, unprovoked, into his closing statement at the Feb. 13 Republican debate.

“We are going to be a country that says that life begins at conception and life is worthy of the protection of our laws,” he said. “We’re going to be a country that says that marriage is between one man and one woman. We are going to be a country that says the Constitution and the rights that it talks about do not come from our president, they come from our creator.”

In 2008, and especially in 2012, such a statement would not have surprised anyone. But this year, same-sex marriage no longer seems as prominent an issue in the GOP campaign. Though “preserving and protecting traditional marriage” remains in the official GOP platform, the Conservative Political Action Conference this month approved the Log Cabin Republicans as a conference sponsor after having been accused of discriminating against the pro-gay-marriage organization by rejecting their request to participate in previous conferences.

And in the Republican presidential debates, “same-sex marriage” and variations of that term have come up less frequently than they did in GOP debates during the 2012 and 2008 primary elections.

The chart above shows totals, but on average, “gay marriage” and its variants have only come up up 4.45 times per debate so far in this year. It came up 6.75 times per debate in 2012 and 5.13 times per debate in 2008.

Has the Republican Party all but given up on same-sex marriage? There seems to have been a shift since the Supreme Court’s 2015 ruling that legalized same-sex marriage nationwide. But Gregory Angelo, president of the Log Cabin Republicans, says that the change started earlier — that the GOP learned from its mistakes in 2012, when the Republican electorate began to split on same-sex marriage. No longer a wedge issue that worked to the party’s advantage, it became a divisive topic within the party, prompting this statement in its post-2012 election report: “We need to campaign among Hispanic, black, Asian, and gay Americans and demonstrate that we care about them, too.” Now, Angelo says, standing against gay rights will not win you many votes.

Just hours before the South Carolina primaries, he said, “a robocall went over from a Ted Cruz super PAC that said if Donald Trump were president, you could expect forward motion on gay rights. Four years ago, eight years, ago, an ad like that could turn the dime.”

Instead, Trump, who has flip-flopped on same-sex marriage several times, won the state primary, including 34 percent, a plurality, of the evangelical vote. His win may be due, in part, to rapid changes in the GOP electorate. According to the Pew Research Center, while evangelicals are the party’s largest constituency nationwide, 14 percent of Republicans had no religious affiliation in 2014, up from 10 percent in 2007. And 61 percent of young Republicans support same-sex marriage. Paris Dennard, a GOP strategist, says more conservatives are leaning libertarian, meaning that they believe in limited government, even when it comes to gay marriage.

Not everyone has given up the marriage fight. But Russell D. Moore, president of the Ethics and Religious Liberty Commission, a unit of the Southern Baptist Convention that advocates Christian values to government leaders, acknowledges that the conversation has shifted.

Whatever their definition of marriage, he says, Americans should be concerned by the Supreme Court’s decisions, “both in terms of the power of the government” and “the reasons given for the redefinition.”

“I think that’s where the conversation is now,” he went on. “What sort of justices and judges would a president appoint, and how would they be restricted by a constitution itself?”

The shift from talking directly about same-sex marriage to more glancing references is also reflected in the GOP debate rhetoric. Mentions of “religious,” “religious liberty” and “religious freedom” appeared more than ever in this year’s debates when referring to the rights of business owners to refuse services to gay customers. It’s code, Dennard says, for “gay marriage.”

“What you can fight about is the ramifications of it,” he said, “that it affects small business, that it affects Christianity. What is the root issue? Christianity is under attack. You can say that ‘values are under attack’ without coming out against gay marriage.”

The shift has strategic significance, too. Gay marriage has long been a gateway issue, an important indicator for many voters as to whether the party shares their fundamental values. By standing against gay marriage, the party risks alienating new members. The shift is also, as Dennard notes, an indicator of how diverse the party really is.

“You have people who are gay and in the party. The Republican Party is not a monolithic group. We are diverse,” he said. “But the question is, at the end of the day, who is going to be able to win, and how can you galvanize the people to feel a part of the party, while still maintaining an essence of the party?”

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