The new auto tariffs are straining relations with U.S. allies and deepening doubts about America’s reliability as a partner.
In a late-night social media post, the president said he would impose “large scale” tariffs if Canada and the European Union allied to “do economic harm” to America.
Leaders in both countries warned that tariffs would fan inflation in the United States and upend global supply chains.
Trump officials have demanded more European military spending and questioned the continent’s values. Leaked messages show the depth of the rift.