The deadline for the duties to go into effect are still three weeks, which may mean the announcements could be a negotiating move.

While Mexico was spared from Trump's so-called "Liberation Day" tariff rollout on April 2, the 30% rate for the E.U. is 10% higher than what the president said he would apply to America's largest trading partner in April.

President Donald Trump posted letters to the leaders of Mexico and the European Union, saying they had not done enough to head off the new tariffs.

It shows that personal grudges rather than simple economics are a driving force in the U.S. leader’s use of tariffs.