Former Arkansas Gov. Mike Huckabee was a Republican presidential hopeful in the 2008 election. He writes that he wants his book God, Guns, Grits, and Gravy to introduce Americans to life in "flyover country." Justin Sullivan/AFP/Getty Images hide caption

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Former Arkansas Gov. Mike Huckabee speaks at the Republican National Convention Wednesday. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

Sen. Bill Frist (left) gives a mock smallpox vaccine during a training session in 2003. Frist, a surgeon, once gave CPR to a visitor who collapsed in a Senate office building. Susan Walsh/AP hide caption

itoggle caption Susan Walsh/AP

Former Massachusetts Gov. Mitt Romney speaks to the Values Voter Summit, held by the Family Research Council Action, Friday, Sept. 17, 2010, in Washington.  Jacquelyn Martin/Associated Press hide caption

itoggle caption Jacquelyn Martin/Associated Press