Farm exports to China are down, manufacturing job growth has stalled, and prices are up for many goods Americans are about to enter the third full year of President Donald Trump’s aggressive tariff regime, which aims to promote US manufacturing, protect key industries, and prompt other nations to reduce their trade barriers. So, it’s a good time to stop and ask whether tariffs are producing the results desired by the president and other supporters of his trade policies. It’s an important question for America’s economic future as well as for the president’s reelection chances. But with...