Could Rob Portman Make GOP Evolve on Marriage Equality?

While the candidates seeking the Republican presidential nomination are trying to outdo each other on opposition to marriage equality, some party leaders think that stance is a liability -- and they're looking to U.S. Sen. Rob Portman, father of a gay son, to change it, CNN reports.

Social conservatives are vowing to keep a plank opposing same-sex marriage in the party's platform at next year's convention, no matter what the Supreme Court decides on marriage equality this summer, but "a mix of Republican leaders who think it's time to drop that language -- they think it hurts the party -- they're pushing Sen. Portman to take a lead role in the platform debate," CNN's John King said on Inside Politics Sunday, without naming the leaders.

Portman in 2013 became the first Senate Republican to support marriage equality, having changed his mind on the issue after his son Will came out to him two years earlier. And the 2016 Republican National Convention will be held in Cleveland, in Portman's home state of Ohio. These two factors make Portman well-positioned to spearhead an effort to change the platform, King noted, although the fact that he's up for reelection to the Senate could make him reluctant to do so. The Republican convention is set for July 18-21, 2016.

The Republican platform has contained language opposing marriage equality for several election cycles, and it was strengthened in 2012. That year the Democratic Party became the first major U.S. political party to include a pro-marriage equality plank in its platform.

Watch the Inside Politics clip below.