Almost nine years ago, I wrote that I would not support Mr. Trump's candidacy:Mr. Trump has not laid out a coherent economic worldview, but one recurrent theme is hostility to a free and open system of international trade. From my perspective as an economics policy wonk, that by itself is disqualifying. I am not a psychologist, so I cannot figure out what Mr. Trump's personal demons are. But he does not show the admirable disposition that I saw in previous presidents and presidential candidates I have had the honor to work for. Sadly, today's announcement about tariffs makes clear that I was right.