In case you haven’t heard, tariffs are here

Well, it happened.

President Donald Trump’s long-proposed 25% tariffs on Mexican and Canadian goods took effect on Tuesday, rattling markets and potentially setting the stage for a global trade war. The US also added to its tariffs on China, slapping the country with an extra 10% tariff on imports, for a total of 20%.

Retaliation was swift. Canada said it would impose 25% tariffs right back. China plans to impose extra tariffs of 15% on US agricultural products like wheat and corn. The country is also suing the US with the World Trade Organization. Mexico said it would announce retaliatory measures against the US on Sunday, which will include both tariff and non-tariff actions.

Leaders and representatives of impacted countries were fierce in their criticism of Trump’s decision, with Canadian Prime Minister Justin Trudeau saying the US has now “chosen to launch a trade war that will first and foremost harm American families.”

Trudeau went on to say that Trump’s damage to the Canadian economy has “started this morning, but he is rapidly going to find out, as American families are going to find out, that that’s going to hurt people on both sides of the border.”

Meanwhile, Chinese foreign ministry spokesperson Lin Jian stressed that the country and its people “have never believed in coercion or intimidation, nor do we succumb to bullying and hegemonic tactics.”

The Trump administration has championed tariffs, which the president once described as “the greatest thing ever invented,” as a boon to manufacturing jobs and a valuable trade tool, though it didn’t really play out that way during Trump 1.0.

This time around, given the magnitude of the tariffs and the dramatic retaliation from other countries, many economists forecast dismal results if the steep tariffs stay in place.

After the tariffs went into effect on Tuesday, Andrew Wilson, deputy secretary-general of the International Chamber of Commerce, told the Wall Street Journal he feared a crash similar to the Great Depression.

“Our deep concern is that this could be the start of a downward spiral that puts us in 1930s trade-war territory,” he said. “Right now it’s a coin-flip. It comes down to whether the US administration is willing to rethink the utility of tariffs.”