Ever since Donald Trump entered the Republican presidential race, I've been a Trump-skeptic. I understood his appeal. I got why angry and alienated Republican rank-and-file voters have glommed onto his campaign. And I could even sketch out a scenario in which Trump could win. Yet, even as his poll numbers rose and he seemed immune from the political pitfalls that usually fell first-time candidates, I couldn't quite buy the notion that Trump, former reality star and full-time blowhard, could be the Republican nominee for president. It all just seemed too far-fetched. Surely, at some point Trump would implode. Those doubts...