The Republican candidates will debate again tonight on foreign policy. But this time around, Newt Gingrich is leading in the polls. It's a major comeback for Gingrich who started out ahead and took a heavy hit early on. He's now doing one percentage point better than former front-runner Mitt Romney. But is this just a passing trend? Or is he now a serious contender?
Steven M. Gillon is the author of "The Pact: Bill Clinton, Newt Gingrich, and the Rivalry that Defined a Generation." He's also a professor of modern U.S. history at the University of Oklahoma and the resident historian of the History Channel.