Not long after “Hockey Night in Canada” began on the big screens of a bar in Windsor, Ontario, fans in the arena could be heard delivering an icy message as the visiting team’s national anthem was played. They booed, long and loud.
The visiting team was the Minnesota Wild, the anthem was “The Star-Spangled Banner,” and the game in Ottawa on Saturday was taking place hours after President Trump imposed heavy trade tariffs on Canadian imports.
Windsor is the automotive capital of Canada, and a city where the flag lauded in the booed American anthem can often be seen flapping beside its Canadian counterpart. With Detroit just across the border, A.T.M.s in Windsor disburse both U.S. and Canadian dollars.
And so Mr. Trump’s decision to impose damaging 25 percent tariffs on most Canadian exports and 10 percent levies on energy exports has set off waves of anger and worry in Windsor, and a sense, for many people, of deep disappointment and helplessness.
The tariffs, a stunning departure from the norm in modern relations between the two countries, has raised concerns about a swift shutdown of local auto plants, as well as car factories in Detroit across a river that at some points is only a half-mile wide.
Mr. Trump’s suggestions, repeated again on Sunday, that Canada abandon its sovereignty and throw in its lot with the United States merely added insult to injury. Canadians in Windsor viewed the American president’s idea as — to put it mildly — profoundly unneighborly.