On Dec. 10, 1991, a conservative pundit who had worked for three presidents and become a celebrity by hosting a cable television debate show declared he would run for elected office for the first time – and not just any office. Pat Buchanan, a veteran of the Nixon, Ford and Reagan White Houses, announced his campaign for the presidency in front of a small yet raucous gathering of his supporters in New Hampshire. He would challenge in the upcoming primaries incumbent Republican President George H. W. Bush who, in Mr. Buchanan’s view, was a globalist who had lost touch with...