A post on Truth Social by President Elect Donald Trump shattered the calm that had fallen on Washington DC in the days ahead of the Thanksgiving holiday when the U.S. Congress was in recess. The post read:

President-elect Donald Trump intends to follow through on his plan to impose sweeping tariffs on America’s top trading partners — a move that could come at a high cost to U.S. consumers. On Monday, Trump promised a new tariff on all products entering the U.

The president-elect’s opening salvo in trade and border talks with the United States’ neighbors is casting a harsh light on the North American alliance.

Trump said Monday on Truth Social that one of his first executive orders would be to hit Mexico and Canada with a blanket 25% tariff. Mexico and Canada are the second and third top suppliers of goods to the U.S., according to the Office of the U.S. Trade Representative. The U.S. imports the most goods from China.

President-elect Trump’s pledge to impose tariffs on Mexico and Canada threatens to upend decades of North American integration, a bumpy process that’s recast the two U.S. neighbors as providers of raw and finished goods for the world’s biggest economy.

Texas Sen. Ted Cruz (R) defended President-elect Trump’s threat to impose steep 25 percent tariffs on all goods from Canada and Mexico — two key U.S. allies — pointing out that the remark produced “immediate” action.