Sen. Rob Portman (R-Ohio) has become to first Republican U.S. senator to support marriage equality (Photo public domain)

In a surprising and historical development, U.S. Sen. Rob Portman (R-Ohio) on Thursday became the first sitting Republican senator to come out in favor of same-sex marriage.

Several media outlets reported this news late Thursday night. The Ohio Republican said he grew to support marriage equality after his son Will, a student at Yale University, came out as gay to his family two years ago and said he’d been that way as long as he can remember.

Explaining his “change of heart” in an exclusive interview with CNN’s Dana Bash, Portman said his previous position, which was rooted in faith, changed after that “very personal experience.”

“That launched an interesting process, for me, which was kind of rethinking my position, talking to my pastor and other religious leaders, and going through a process of — at the end — changing my position on the issue,” Portman said.

Portman expressed a similar sentiment to reporters in his office, according to another report in the Cleveland Plain Dealer.

“It allowed me to think of this issue from a new perspective, and that’s of a dad who loves his son a lot and wants him to have the same opportunities that his brother and sister would have — to have a relationship like Jane and I have had for over 26 years,” Portman was quoted as saying.

Media outlets reported Portman said he later came to support marriage equality after he consulted former Vice President Dick Cheney, a marriage equality supporter whose daughter Mary Cheney is a lesbian.

Moreover, Portman reportedly said he believes part of the Defense of Marriage Act, which is currently under review by the U.S. Supreme Court, should be repealed. Section 3 of that law prohibits federal benefits from flowing to married same-sex couples.

Still, Portman reportedly emphasized he doesn’t want to force his views on others and religious institutions shouldn’t be forced to perform weddings or recognize marriages against their tenets. The Ohio Republican said he doesn’t know what the political fallout of his new position will be.

Portman’s new position marks a significant turnaround from his voting record as a member of the U.S. House of Representatives from 1993 to 2005. During his tenure in the lower chamber of Congress, Portman voted for DOMA and a proposed constitutional amendment that would ban same-sex marriage in 2004.

While no other Republican members of the U.S. Senate support marriage equality, two sitting GOP House Republicans do: Reps. Ileana Ros-Lehtinen (R-Fla.) and Richard Hanna (R-N.Y.). They both were among 131 prominent Republicans who signed a legal brief urging the Supreme Court to overturn California’s Proposition 8.

Portman isn’t the first Republican U.S. senator to back marriage equality, although he’s the only current member of the Republican Senate caucus to hold that position. Lincoln Chafee is considered the first because he supported legalizing same-sex marriage as a Republican U.S. senator before becoming an Independent and being elected governor of Rhode Island.

One question is where Portman now stands on the Employment Non-Discrimination Act. Asked about the issue last year by ThinkProgress, Portman expressed caution over the legislation and withheld immediate support.

“What I’m concerned about in Paycheck Fairness and other legislation like that is the fact that it will spawn a lot of litigation the way the legislation is written,” Portman said at the time. “So you don’t want it to be a boon to lawyers, you want it to actually help people. But no one should discriminate.”

But in June, Shari Hutchinson, a lesbian Cleveland, Ohio, resident, and member of the LGBT group Freedom to Work’s Speakers Bureau, told the Washington Blade she met privately with Portman’s staff and left feeling optimistic the Ohio Republican would support ENDA.

“I am an Ohio voter and I met with Sen. Portman’s staff last month to tell them how I faced anti-lesbian slurs at work in Cleveland and how I was repeatedly denied promotions even when the heterosexual candidate they selected instead of me had failed the qualifying exam for that promotion,” Hutchinson said. “Mr. Portman’s staff was very attentive, respectful and concerned to hear that anti-LGBT workplace harassment and discrimination still goes on in Ohio. I urged them to support ENDA and I am hopeful Mr. Portman might do the right thing.”

Portman was on the short list of possible vice-presidential contenders for 2012 Republican presidential nominee Mitt Romney. Among LGBT advocates, he was seen as a lackluster candidate at the time because of his support for the Federal Marriage Amendment and reluctance to support the Employment Non-Discrimination Act.

Gregory Angelo, executive director of the National Log Cabin Republicans, said in a statement Portman’s new position demonstrates the growing support for marriage equality among the GOP.

“If there was any doubt that the conservative logjam on the issue of civil marriage for committed gay and lesbian couples has broken, Sen. Portman’s support for the freedom to marry has erased it,” Angelo said. “Sen. Portman’s evolution on this issue highlights how personal it is for Americans — whether they’re the junior senator from Ohio or your next-door neighbor, all Americans have a gay friend, colleague or family member, and understand them to be as deserving as their straight counterparts of the inalienable rights of life, liberty, and the pursuit of happiness that are the promise of the United States.”

Angelo added Portman’s support for same-sex marriage demonstrates a person can support same-sex marriage while holding religious views.

“We also applaud and respect the Senator’s decision as a person of faith who recognizes that there is a Christian case as well as a conservative case for marriage equality,” Angelo said. “Log Cabin Republicans welcomes Senator Portman’s support, and encourages his GOP colleagues in the Senate to join him on the right side of history.”

CORRECTION: An initial version of this article incorrectly reported that Portman is the first GOP U.S. senator to back marriage equality. It also mischaracterized a quote from Gregory Angelo. The Blade regrets the errors.