In any case, the relevant legislation gives the occupant of the White House remarkable leeway should he choose to go protectionist. He can restrict imports if such imports “threaten to impair the national security”; he can impose tariffs “to deal with large and serious United States balance-of-payments deficits”; he can modify tariff rates when foreign governments engage in “unjustifiable” policies. Who determines whether such conditions apply? The executive himself.

Image Peter Navarro, center, was chosen by President-elect Trump to lead a new White House office overseeing American trade and industrial policy. Credit... Andrew Harrer/Bloomberg

Now, these provisions weren’t intended to empower a president to reverse decades of U.S. trade policy, or engage in personal vendettas. You can guess, however, how much such niceties are likely to bother the incoming administration, which is already talking about using its powers. Which brings us to the question of motive.

Why would a Trump administration impose restrictions on imports? One answer is those working-class voters, whose supposed champion is set to pursue a radically antiworker domestic agenda. There’s an obvious incentive for Mr. Trump to make a big show of doing something to fulfill campaign promises. And if this creates international conflict, that’s actually a plus when it comes to diverting attention from collapsing health care and so on.

Beyond this, it’s clear that the incoming commander-in-chief really believes that international trade is a game in which nice guys finish last, and that America has been taken advantage of. Furthermore, he’s picking advisers who will confirm him in these beliefs.

Oh, and don’t expect attempts by experts to point out the holes in this view — to point out, in particular, that the image of a predatory China, running huge surpluses by keeping its currency undervalued, is years out of date — to make any impression. Members of the Trump team believe that all criticism of their economic ideas reflects a conspiracy among think tanks that are out to undermine them. Because of course they do.