Why Donald Trump bothered to issue an economic program is beyond me. It has some good things in it, like raising the tax on carried interest, but no one really cares about Trump’s economic plan — no matter his supposed expertise. He says he’s a businessman who knows about such things. His supporters don’t care that he’s a builder. They care that he’s a destroyer. The impetus for the Trump campaign is President Obama. He represents a historic, even cataclysmic, change in U.S. political life and, for some, what the United States is supposed to be about. One of the...