Republican Sen. Rob Portman of Ohio said his support for marriage equality puts him at odds with his party and "probably makes it difficult" to "win a primary election at a national level." Portman made the comments in an interview with Hoover Institute fellow Peter Robinson that was posted online Tuesday.

"Republicans ought to treat people as they are," Portman said, and supporting marriage equality is a "conservative position."

"It puts me at odds with my party in many respects," Portman said. "I believe it's a conservative position."

Portman said he "never really thought deeply" about the issue of marriage equality until his son came to him and his wife and told them he was gay.

"I never really thought deeply about it. It seems to me to the extent that it's not a choice, which is what I believe. That is, Republicans ought to treat people as they are."

When the interviewer brought up the 2016 presidential election and speculation that he might run, he said supporting marriage equality would making winning the primary difficult. "It probably makes it difficult for me to win the primary election at a national election."