On the surface, things are looking pretty good for Donald Trump’s efforts to capture the Republican nomination. He’s received more votes, and has more pledged delegates, than any other candidate. After Missouri certified its race on Tuesday, Trump’s delegate lead was 755 to 545 over Sen. Ted Cruz, with 1,237 needed to win the nomination. Trump is about to overwhelmingly capture his home state of New York, and is poised to do nearly as well in Pennsylvania. And Trump has the full backing of some crucial parts of conservative media, notably The Drudge Report. And yet there’s an increasing desperation...