The Trump administration on Sunday warned that Canada would be “foolish” to think it could win a trade war with the United States, predicting a “devastating” impact on its northern neighbour. Negotiations between Washington and Ottawa broke down late Friday, putting into force new 50 per cent US tariffs impacting about US$20 billion worth of Canadian goods, or 5.5 per cent of Canadian exports to the US. Canada in retaliation said it would match US tariffs, with new levies notably targeting the...