Prominent economists are divided on trade. The lead-author’s dissertation advisor, University of Chicago economist Milton Friedman, favored free trade, but he was mostly writing when the U.S. had a trade surplus.
In contrast, British economist John Maynard Keynes supported tariffs when Britain was experiencing trade deficits. In 1931 he proposed (in what was called the addendum to the Macmillan Report) a system of tariffs upon British imports to be used to subsidize British exports in order to balance British trade.
During World War II, Keynes tried to set up a postwar system that would keep trade in balance by letting trade-deficit countries, but not trade surplus countries, impose tariffs and/or reduce their exchange rates. But he was overruled at Bretton Woods, where the postwar international agreements were negotiated, by America’s chief negotiator Harry Dexter White, a Soviet agent.
Economic history shows that the effect of tariffs depends upon trade balances. When trade is balanced, all trading partners benefit, but benefit could increase even more in the absence of tariffs. When trade is not in balance, countries sometimes use tariffs and other barriers to imports and/or subsidies to exports to gain a trade surplus, what 18th Century Scottish economist Adam Smith called a policy of “beggaring all their neighbours.” Their economies grow at the expense of their trading partners.
Countries with trade surpluses grow in relative power, while those with trade deficits shrink. For example, Bill Clinton’s trade agreement with China led to steadily worsening trade deficits, with concomitant transfer of U.S. economic growth and political power to China.