Justin Trudeau has announced he will step down after nine years as Canadian prime minister in the face of a mounting set of crises, but stay in office until a replacement party leader is chosen.

The core message is clear: we make things together. Almost two-thirds of Canadian exports to the US and half of US exports to Canada are intermediate inputs in integrated supply chains. Tariffs will reduce GDP and increase consumer prices in both countries. When Canada retaliates on US exports to Canada—as it will—the impacts will be harsher.