Former U.S. President Donald Trump speaks at the Minden Tahoe Airport in Minden, Nev., on Oct. 8.José Luis Villegas/The Associated Press He criticized a former Republican president, George H.W. Bush, and survived. He pilloried a one-time GOP presidential nominee and military hero, John McCain, and flourished. He took on another Republican nominee, Mitt Romney, and emerged unscathed. He suggested that the father of a 2016 Republican nomination rival, Ted Cruz, was involved in the assassination of John F. Kennedy and still got an Oval Office picture with the Cruz children. He denounced the leader of the Republicans in the House...