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.

President Trump is threatening the European Union and Mexico with 30% tariffs. The EU warns of counter measures if the tariffs kick in on Aug. 1.

S&P 500 futures lost 0.5%, while Nasdaq 100 futures dropped 0.6%. Futures for the Dow Jones Industrial Average fell 204 points, or 0.5%.

If he moves forward with the tariffs, it could have ramifications for nearly every aspect of the global economy.

Financial markets, which have shown increasing insensitivity to tariff threats from the US, will face a test at the Monday open after President Donald Trump declared a 30% rate for the European Union and Mexico effective Aug.

If a 30 percent tariff on Mexico goes into affect on August 1, a wide variety of foods will be more expensive, experts warn.

America’s biggest trading partners have tried tactics ranging from appeasement to retaliation to avoid higher tariffs. All find themselves faced with similar threats from Washington.

Businesses typically pass tariff costs onto consumers through higher prices. Sometimes, that process is less subtle.