Trump’s promise to impose 30% tariffs on imports from Mexico and 35% on imports from Canada beginning tomorrow could hammer up to three-fourths of their U.S. imports.

U.S. President Donald Trump on Thursday signed an executive order increasing tariffs on Canadian goods to 35% from 25% on all products not covered by the U.S.-Mexico-Canada trade agreement, the White House said.

Commerce Secretary Howard Lutnick reminded us of an important but little-discussed part of trade negotiations with Canada and Mexico -- "virtually 75%" of trade between the U.S. and its two neighbors is "already tariff free" because of the USMCA agreement.