Prime Minister Mark Carney speaks in Ottawa, Ontario, Canada, May 5, 2026. Polls show that Canadians strongly back Carney’s decision to end trade talks with Washington last month and to hit back with tariffs on about $20 billion in U.S. products entering Canada. But there is also concern over what might happen next. (Ian Austen/The New York Times) By IAN AUSTEN After more than two weeks of finger-pointing, threats and patronizing insults between longtime trading partners, Canada’s latest…