The odds would be stacked against Rob Portman, but it's not impossible.
48.8 percent of gay Americans live in states that allow gay marriage.
Rep. Richard Hanna (R-N.Y.) won Tuesday, but his tight race will make like-minded pols think twice.
Strong gay marriage opponents say the issue isn't that important to their vote.
19 states allow same sex marriage. President Obama won all 19 in 2008 and 2012.
Despite living in fewer than half of the states, back-of-the-envelope calculations suggest that just about half of the American gay population lives in a state that allows marriage.