President Donald Trump? Really? How are we to understand this astonishing development, and what does it say about voters? I believe that last weekend’s Trump rally attended by 30,000 people in a football stadium in Mobile, Alabama, gives us a clue. For almost the entire 53-minute speech, Trump mentioned only three policy issues. First he talked about illegal immigration, saying that Americans have been killed and raped by illegal immigrants, and that the only solution is his famed plan to build a wall between the United States and Mexico. Then Trump talked about Ford and Nabisco moving their factories and...