Hoover, who is also a CNN political commentator. Hoover runs the American Unity PAC, which spent more than $4 million in the 2014 cycle to support pro-gay marriage and LGBT rights Republican candidates, according to the group's pre-election Federal Elections Commission filing. The GOP could see at least one pro-gay marriage presidential candidate in the 2016 elections if Sen. Rob Portman -- who has a gay son and endorsed same-sex marriage in 2013 -- decides to seek the party's nomination. When Mitt Romney was the nominee of the party, could you have imagined that there could be a Republican nominee the next time around who is in favor of same-sex marriage ? Even I could n't have imagined that, Hoover said. Same-sex marriage: Fast facts What's next in the fight over same-sex marriage ?