CHICAGO (AP) — President Donald Trump’s barrage of tariffs — and threats of even more — has strained the United States’ longstanding relationship with Canada.

Over the course of his second term in office, Trump has threatened Canada’s economy and sovereignty with steep new import taxes on its goods. He’s gone as far as suggesting that his northern neighbor could be “the 51st state.” That rhetoric — paired with volleys of on-again, off-again new tariffs — has outraged Canadians, whose government has responded with its own retaliatory measures. All the while, uncertainty for businesses and consumers across both sides of the border only grows.