US–Canada trade talks have collapsed and Canada is hitting back with tariffs — bad for shoppers and businesses on both sides of the border, and a fresh sign that no US trade deal is safe.

• Talks broke down after last-minute US demands, and Canada will start retaliatory tariffs on September 8.
• Carney says Canada was attacked and is treating this as an economic war, pointing to a US tariff hit of 50%.
• New US tariffs cover everyday goods — wine, furniture, dairy, cement, clothing, fishing rods, hockey gear — so American prices go up on ordinary stuff.
• Canada's biggest card is energy: it supplies almost all of America's imported natural gas, most of its imported electricity, and most of its imported crude.
• The Canadian boycott is already biting: US whiskey and spirits sales to Canada fell about 70%, even as they grew everywhere else.

Outlook: No new talks are scheduled — the US trade team has moved on to Brazil, so tariffs on both sides look set to bite through the fall.