(CNN) – South Carolina Sen. Lindsey Graham has always enjoyed a little back-and-forth with belligerent audiences. He was at it again on Monday night as he faced down an angry town hall crowd in Greenville packed with libertarians and Tea Party activists who accused at the Republican senator of ditching conservative principles by working with Democrats on issues like climate change and voting to send Sonia Sotomayor to the Supreme Court. But Graham stressed a mantra he's repeated many times since his friend John McCain lost the presidential election last November — that the GOP must reach out to different...