The rationale behind this evolution is pretty simple, Gregory T. Angelo, executive director of Log Cabin Republicans, a conservative group that advocates for marriage equality, told TPM. It's a recognition of the growing American acceptance of same-sex marriages -- 54 percent supported it in a July 2013 Gallup poll, a new record high -- and that opposition will not be a tenable position for the GOP over the long term. There's plenty of evidence to suggest that: A March 2013 Washington Post/ABC poll found that 52 percent of Republicans ages 18 to 49 supported marriage equality.
"What you're seeing is a shift in the Republican Party, where Republicans are no longer walking in lockstep in opposition to marriage equality," Angelo said. "In fact, supporters are not silent, but very involved in declaring their support. I think there is an understanding by some of the braver Republicans out there that the time is now to step up in support of marriage equality. It will impact their legacy and how they go down in history."
Some national Republicans have voiced support for gay marriage, most notably Sen. Rob Portman (R-OH), whose son is gay, but Angelo said this is an issue where change is likely to spread from the local and state level up to the national party.
Sen. Rob Portman (R-OH)
In recent weeks and months, the transition has become more and more evident as marriage equality battles intensify across the country. And if the trend toward marriage equality is to continue in more conservative states, pro-gay marriage Republicans will likely become even more fundamental to the fight.
The Statesman Journal reported last week on Oregon Republicans who were joining the campaign to overturn that state's constitutional ban on gay marriage via a ballot initiative in the November election. They have been filming videos as part of the ongoing effort. Two dozen GOP officials and activists have joined the conservative group, Freedom Oregon, forwarding the cause.
“It shows just a sea change in the past 10 years,” Jim Moore, a professor at Pacific University, told the newspaper. “It’s not just opinion polls saying the world is changing, but the political establishment is saying we also need to move to same-sex marriage.”
Some GOP officials in Indiana and New Mexico, states where Republican leadership has advanced efforts to prohibit same-sex marriages, have publicly stood against those plans -- evidence, particularly in the case on Indiana, that this new sentiment is creeping into more conservative states and Republicans are more comfortable taking public stands in those states.
"I'm happy with the Supreme Court's decision," Rep. Jim Smith, a New Mexico Republican, told the New Mexican of the state supreme court's decision to stop the state's ban on same-sex marriage. He said he would vote against a proposal pushed by his GOP colleagues to overrule the court and reinstitute the ban.
In Indiana, a top Republican operative headed a bipartisan coalition to stop Republican legislative leadership from advancing a constitutional prohibition on same-sex marriages. The effort has attracted a number of notable GOP mayors to its cause, including the Republican mayor of Indianapolis, and 11 conservative state legislators joined 29 Democrats to oppose the bill last week, though it still cleared the House and is headed to the Senate.
"Everyone else in the country is moving toward more equality. Indiana is kind of the last stand of folks that are trying to put something like this into their constitution," Megan Robertson, the GOP operative, told the Associated Press.
Conservative gay-marriage supporters view non-action as equally notable, pointing to Christie and Martinez as examples of high-profile GOP governors, both of whom have had their names linked to the 2016 presidential and vice presidential nominations, who have tacitly accepted gay marriage in their states.
"I think what I said before was that ‘yes, the people should have decided on it,’ but the Supreme Court has decided," Martinez said of the court ruling. "And it's now the law of the land."
New Mexico Gov. Susana Martinez (R)
Looking ahead, these Republicans willing to embrace marriage equality should become even more important. Advocates hope that the evolution of Republicans in Democratic-controlled states like Oregon will influence their peers elsewhere.
"Changing hearts and minds in red states now builds on the example of those Republicans who stood on the right side of history in blue states," Stuart Gaffney, a spokesman for Marriage Equality USA, said in a statement to TPM. "The momentum for the freedom to marry appears to be truly unstoppable now."
Republicans will become critical because as more blue states allow gay marriage, that will leave the GOP-controlled states as the next frontier, Angelo said. There, more alliances between progressives and pro-same-sex marriage conservatives will likely be necessary to achieve what has come easier in more moderate states.
"Unless you engage with Republicans, the only parts of the country that are going to be support of marriage equality are going to be blue states," he said. "I think there is an understanding if you want to have marriage equality outside of progressive pockets of the country, you need Republicans onboard."