Trudeau’s politics and worldview might not align with Trump’s, but he was among the first world leaders to congratulate the U.S. president on his election victory, noting Canada has “no closer friend, ally, and partner than the United States.” It’s a message he carried to Washington where he endured an awkward handshake with Trump, and had what was generally billed as a positive meeting with the American president. When it ended, the two men spoke warmly of each other, and Trump even said he was prepared to tweak NAFTA instead of withdrawing from it.

But on Thursday, Trudeau seemed particularly aggrieved by the national-security grounds on which the Trump administration imposed the tariffs. He said Canada was America’s “most steadfast ally” in war and peace, calling the tariffs “an affront to the … thousands of Canadians who have fought and died alongside American comrades-in-arms.” But what he said next perhaps illustrates just how poor relations between the two neighbors have become.

“In closing, I want to be very clear about one thing: Americans remain our partners, friends, and allies. This is not about the American people. We have to believe that at some point their common sense will prevail,” he said in the type of language that successive U.S. administrations have used to describe recalcitrant regimes such as Iran. “But we see no sign of that in this action today by the U.S. administration.”

Trump fired back in a statement late Thursday: “The United States has been taken advantage of for many decades on trade. Those days are over. Earlier today, this message was conveyed to Prime Minister Justin Trudeau of Canada: The United States will agree to a fair deal, or there will be no deal at all.”

On Friday, via Twitter, Trump added: “Canada has treated our Agricultural business and Farmers very poorly for a very long period of time. Highly restrictive on Trade! They must open their markets and take down their trade barriers! They report a really high surplus on trade with us. Do Timber & Lumber in U.S.?” (The U.S. has a $8.4 billion trade surplus in goods and services with Canada.)

The dispute over tariffs is part of a larger trade dispute between the United States and its two neighbors—Canada and Mexico—over NAFTA. Trump says he believes the agreement, which was signed in 1994 and allows for the free flow of goods and services among the three countries, has destroyed American industry, hurt American workers, and eviscerated the American middle class. No amount of data from economists, pleas from farmers who have found massive overseas markets for their produce, and entreaties from the Chamber of Commerce seems able to persuade him otherwise.

NAFTA is being renegotiated by the three countries, but the pact looks set to go the way of the Paris climate accord, the Iran deal, and the Trans-Pacific Partnership. The advisers who advocated for Trump to remain in those multilateral pacts have long left the administration and those who remain say they support Trump’s worldview. Indeed, Wilbur Ross, the Commerce secretary, said Thursday the tariffs on Canada were being imposed because of insufficient progress on talks to renegotiate NAFTA.* Just days earlier, investors were optimistic that the three countries were close to an agreement. No longer.