Canada’s answer to U.S. tariffs arrived at the border.

Canada’s countertariffs on certain U.S. goods took effect Tuesday, with rates of 15%, 25% and 50%. The move answers a U.S. action announced in July: 50% tariffs on nearly $20 billion in Canadian imports. This is independently consequential because the two economies are unusually intertwined; the dispute has now crossed from political leverage into routine border administration. Once tariffs become the daily paperwork of commerce, companies must plan around them even while diplomats keep talking.

Canada put countertariffs on certain U.S. goods into force, escalating a dispute with its largest trading partner from a negotiating threat into an operating cost for cross-border commerce.