Jeb Bush launched his presidential campaign's exploratory committee on December 16, 2014, the presumptive Republican nominee. He ended his campaign on February 20, 2016, a broken man. Bush's campaign (and the pro-Jeb super PAC Right to Rise) spent over $100 million on his campaign. He won no states. And for the last several months, he's been in the news mostly for all the wrong reasons: desperate donors, misspent money, jokes-that-aren't-really jokes. He's been a loser for almost as long as he was a presumptive winner. The slow, torturous twilight of Jeb's campaign offers a couple of lessons. For one thing,...