Mitt Romney made a hastily arranged trip to Charlotte, N.C., on Friday, and not just because that city is the site of the Democratic National Convention. It's because North Carolina looks to be leaning red. President Obama won the state four years ago but his decision to publicly endorse same-sex marriage this week could cost him the Tar Heel state, especially as his announcement came the day after the state rejected an amendment legalizing gay marriage. The Republican National Committee circulated a memo on the state, arguing that the retirement of high-profile Democratic lawmakers in the North Carolina, a sexual...