Only four days left until the South Carolina Republican presidential primary. That means only four days for the candidates to derail front-runner Mitt Romney off the path to the GOP nomination. At last night’s debate in Myrtle Beach Romney fended off attacks on his business record, his personal wealth, and his moral character. Anna Sale  is a political reporter for It’s a Free Country’s who is traveling with The World Channel, a production of WGBH.  Ron Christie  is Republican political strategist and political contributor for the Takeaway.