If you stripped the proper nouns from all profiles about 2016 presidential candidates, the ones about Marco Rubio would be the easiest to identify. While most candidates have one adjective that is always appended to their name, the Florida senator who just announced his campaign today has three. He is young. He is ambitious. He is charismatic. The fact that Rubio is only a few months younger than Senator Ted Cruz, or that his most memorable performance on the national stage was less than charismatic, or that all presidential candidates are by definition ambitious has not lessened the frequency at...