Like the hedgehog, Donald Trump understands only one thing that matters. His critics, such as George W. Bush, Barack Obama, and Jeff Flake, who last week made three largely correct and inspiring speeches, seem to know everything but.

They understand politics, policy, and the uses of etiquette, but seem deaf, dumb, and blind from the central great issue that drove Trump’s election: The top tiers of the country have been flourishing nicely, while those underneath have been taking a beating. And one reason is international trade.