HANOVER, NH—Jon Huntsman walked out of the rear door of a Dartmouth auditorium. His head swiveled as he looked for the black SUV that will take him to his next stop. He had just given a speech emphasizing his claim that the future of America will not be decided on a battlefield in remotest Afghanistan but along the trade routes of the Pacific. The applause had barely died down in the hall as Huntsman exited into the quiet streets of Hanover. He took one second to sigh. He had just launched “Phase Two” of his campaign, and it was a...