The day this article goes up, April 2, has been pegged by President Donald Trump as “Liberation Day”: the day his suite of tariffs will go into effect and thus, in some unspecified sense, liberate the United States.

The pre-history of this disastrous set of policies, which will only make America poorer and alienate it from its closest allies, is as long and weird as you’d expect from Trump. Part of the story seems to involve him losing an auction in 1988 for a piano used in Casablanca to a Japanese collector, thus confirming that Japan was an economic threat. Sure, fine, that seems par for the course with this guy.

But if you want to understand why not only Trump but now large parts of both parties have reoriented themselves to support tariffs, I think the key text is not Casablanca but a 2013 paper by David Autor, David Dorn, and Gordon Hanson that’s almost as famous (among economists, at least). If you follow economic research at all, you know this as the “China shock” paper.

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The authors found that the surge of US manufacturing imports from China between 1991 and 2007 led to large job losses in the US manufacturing sector, losses that were concentrated in a few particular geographic locations. Areas affected saw wages fall for a surprisingly long time, and uptake of government benefit programs like unemployment and disability insurance.

The DC think tank world’s understanding of this finding was sweeping: Free trade didn’t work. Bipartisan advocates like Bill Clinton and George W. Bush had promised that deals like

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