"Make America Great Again" is not a policy. It’s an exercise in mass psychology.

The idea is to get people to displace their anger and frustration onto groups that (in Trump’s view) have eroded America’s “greatness” — Mexicans, Muslims, the Chinese, political and financial elites, and “the media.” The Trump treatment is to peddle hatred and resentment for his political gain.

As an election strategy, this might succeed if enough people subscribe to his self-serving stereotypes. But as economic policy, it’s mostly a dud. It won’t change most people’s objective circumstances. In some cases, it may protect them from imports. But for most, it won’t provide jobs, and any income gains from tax cuts are skewed toward the rich. Sooner or later, people will recognize that they’ve been had.

Trump’s serious deficiencies are of character, not intellect. He is a salesman whose favorite product is himself. His moral code is defined by what works. What works to build his popularity is legitimate, even if it’s untrue, tasteless, personally cruel or inconsistent with what he has said before. What doesn’t work is useless, even if it involves inconvertible truths, important policies or common courtesies.