Canada's $20 billion retaliatory tariffs on US goods took effect overnight as trade talks collapsed, while Republicans gather for an unprecedented midterm convention headlined by Trump seeking voter enthusiasm, and investigators recover flight recorders from a Miami cargo plane crash that killed five people on the ground. Canada and the US have deeply integrated supply chains worth hundreds of billions, with Canada supplying 26 states' largest customer needs and being the top supplier of US oil, electricity, and fertilizer.