A new bill would give the president the power to raise tariffs to match those of other countries (but not to lower tariffs to match). Its sponsor, Representative Sean Duffy (R., Wisc.), says it would encourage free and fair trade. At Bloomberg Opinion, I make the case against the bill.

The course Duffy is recommending seems at least as likely to lead to a product-by-product tit-for-tat, with the U.S. raising tariffs on European cars and the EU raising tariffs on American trucks, as it is to bring tariffs down.

That’s how retaliatory tariffs usually work: One country imposes a tariff in response to another, and then both of them keep these policies, which each inflict damage on both sides’ economies. Our tariff on light trucks from Europe is itself the legacy of a trade war from the early 1960s. . . .