Donald Trump’s threat of 25% tariffs on Mexico and Canada would cost the US economy as many as 400,000 jobs and increase prices for American consumers, according to the Mexican government.

The president-elect said that he would impose the across-the-board tariffs on Day 1 and that they would stay in place until Canada, Mexico and China halted the flow of drugs and migrants.

While the announcement is almost certainly bluster to bring attention to illegal immigration and fentanyl smuggling, there are several reasons why it is so risky.