In the latest NBC News/Wall Street Journal poll, Newt Gingrich has a sizable lead over his Republican rival Mitt Romney. NBC reports: Gingrich leads Romney 37 percent to 28 percent nationally among registered Republicans likely to vote in the primaries; Rick Santorum is in third with 18 percent, and Ron Paul is fourth with 12 percent. There is a bit of a problem for Gingrich, however. "Though Gingrich is the preferred candidate of GOP primary voters, he performs the worst of all Republican candidates tested against Obama, including Santorum," NBC reports. Romney fares best against the president, trailing Obama by...