For the past painful year, the Republican presidential contenders have been bombarding Americans with empty propaganda slogans and competing, bizarrely, to present themselves as the least experienced person for the most important elected job in the world. Democratic primary voters, on the other hand, after a substantive debate over real issues, have the chance to nominate one of the most broadly and deeply qualified presidential candidates in modern history. Hillary Clinton would be the first woman nominated by a major party. She served as a senator from a major state (New York) and as secretary of state — not to...