William Leuchtenburg, according to one reviewer “today’s greatest presidential historian”, and author of “The American President: From Teddy Roosevelt to Bill Clinton,” about what we learned from the New Hampshire primaries about the presidential race and other times when this primary made or broke the campaigns of earlier presidential candidatesWilliam Leuchtenburg, according to one reviewer “today’s greatest presidential historian”, and author of “The American President: From Teddy Roosevelt to Bill Clinton,” about what we learned from the New Hampshire primaries about the presidential race and other times when this primary made or broke the campaigns of earlier presidential candidates