The president’s threats to slap duties on goods imported from the European Union are part of a pattern of directing the harshest penalties at the United States’ closest allies.

Mexico and Canada have managed to avoid U.S. tariffs — for now — after their leaders came to last-minute agreements with President Trump. But barring another eleventh-hour deal, tariffs on goods from China were scheduled to go into force Tuesday, raising the specter of a trade war that could rile the global economy and punish American consumers.