The theory is, of course, backed up by centuries of history and economic analysis. For example, in a 2017 paper, I looked at dozens of government and academic studies examining various eras in U.S. history and found that American protectionism (including and especially tariffs) imposed high economic costs on consumers and the economy more broadly—essentially the theoretical deadweight loss above. However, the studies also showed that tariffs (and other protectionist measures like quotas) typically failed to achieve stated government objectives, such as revitalizing protected industries, saving jobs, or opening foreign markets. At the end of the day, the jobs and industries still withered away (or returned for more government help), and the markets remained closed. At the same time, the protectionism did generate lots of political dysfunction—corruption, incompetence, and the like. Dartmouth’s Doug Irwin came to similar conclusions in his subsequent book on the subject (which, by the way, is a must‐own resource for trade geeks and people generally interested in U.S. economic history).
The Economic Consensus
For these reasons, there are few issues on which more economists agree than eliminating tariffs. For example, in a 2006 survey of 210 Ph.D. economists randomly selected from the American Economic Association, Robert Whaples found that “overwhelming” majorities agreed that “tariffs and import quotas usually reduce general economic welfare,” and that the U.S. government should therefore eliminate remaining tariffs and other trade barriers (87.5 percent), refrain from restricting U.S. employers from outsourcing work to foreign countries (90.1 percent), and nix U.S. anti‐dumping laws (61.3 percent). Other, more recent economist surveys—such as the University of Chicago’s IGM forum—show similar results.
None of this eggheadery, of course, discouraged President Trump from using tariffs for rote protectionist (steel, aluminum, solar panels and washing machines) or geopolitical (China) reasons. This Congressional Research Service report and the accompanying chart below provide the basics—the gray stuff has been threatened, but not actually imposed. (For a more detailed timeline on the measures and their legal bases, go here.)