America's trade war with Canada, Mexico, and China is ramping up. 

All three countries are introducing retaliatory tariffs in response to the steep tariffs introduced by Donald Trump last night. 

Trump's responded, saying he will raise tariffs on Canada even further. 

China's vowing to fight the US "to the bitter end", and Canada's Justin Trudeau says his country won't back down. 

Trudeau says Canadians are reasonable and polite, but they won't back down from a fight when the wellbeing of their country is at stake. 

US Correspondent Richard Arnold told Mike Hosking that within the US, major franchises such as Target, Walmart, Best Buy, and Home Depo are all warning of price spikes ahead.  

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