Consider the following example: pre-tariff, the U.S. imports some good from China that costs $100. Then the Trump administration imposes a 25% tariff, raising the price to consumers to $125. If we just keep importing that good from China, consumers lose $25 per unit purchased – but the government raises an extra $25 in taxes, leaving overall national income unchanged.

Suppose, however, that importers shift to a more expensive source that isn’t subject to the tariff; suppose, for example, that they can buy the good from Vietnam for $115. Then consumers only lose $15 – but there is no tariff revenue, so that $15 is a loss for the nation as a whole.

But what if they turn to a domestic supplier – say, a U.S. company that will sell the product for $120. How does this change the story?

Here the crucial thing is that producing a good domestically has an opportunity cost. The U.S. is near full employment, so the $120 in resources used to produce that good could and would have been employed producing something else in the absence of the tariff. Diverting them into producing what we used to import means a net loss of $20, with no revenue offset.

By the way, in practice any manufacturing jobs added by the Trump tariffs are probably offset by losses of other manufacturing jobs. Partly that’s because most of the tariffs are on intermediate goods – inputs into production, so that job gains in, say, steel are offset by losses in autos and other downstream sectors. Beyond that, the tariffs have probably contributed to a rising dollar, which makes U.S. exports less competitive.

Putting it all together, the Trump tariffs have raised consumer prices, rather than depressing foreign earnings. Some revenue has been gained, but there has also been what amounts to tax avoidance as consumers turn to other, untaxed sources of what we used to import. But this tax avoidance itself comes at a cost, so the U.S. as a whole is left poorer.

Now, the numbers aren’t that big. The new paper puts the net welfare loss at $1.4 billion a month, or $17 billion a year; that’s less than 0.1 percent of U.S. GDP. But winning it isn’t. And the numbers could get a lot bigger if the trade war expands, say with a “national security” tariff on European cars.

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