Just as the Trudeau-hosted G7 meeting of the world's leading industrialized nations had seemed to weather Mr. Trump's threats of a trade war, the president backed out of the group's joint statement that Trudeau said all the leaders had come together to sign.
After the G-7 summit in Quebec Saturday, Trump tweeted aboard Air Force One that the United States would not sign a joint statement.
Mr. Trudeau's office responded to Mr. Trump's tweets accusing the Canadian leader of "false statements" on Saturday, saying that the Prime Minister said nothing during the G7 summit that he had not said previously.
In a tweet posted Saturday evening, Trump said his decision was based on "false statements" made by Trudeau during a press conference he gave, as well as "the fact that Canada is charging massive Tariffs" on US companies.
She took particular issue with Trump's previous claim that imports of Canadian steel and aluminum had made USA steel and aluminum plants unsustainable, thereby threatening national security.
France and Germany both reacted with anger to Mr Trump's decision. Canadians, he said, "will not be pushed around".
Former prime minister Stephen Harper also shared his perspective on the trade spat between Canada and the U.S. Harper said that although he could understand the United States wanting better trade relations with countries like China and Mexico, he can't "understand the obsession with trade relations with Canada".More news: Sandra Bullock on Bonding with All-Female 'Ocean's 8' Cast
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"If a deal isn't made, that would be a very bad thing for Canada and it would be a very bad thing for Mexico", Trump said. His tweet also accused the prime minister of being "dishonest and weak", and claimed that he only placed tariffs on aluminum and steel in response to Canada's "270% on dairy!"
"Prime Minister Trudeau may reap some political benefit through feuding with President Trump, but by engaging with the president on the terms he has so far, instead of on mutually productive ones, he is imperiling the economic well-being of millions of Canadians and Americans", he added.
Sen. Dianne Feinstein, California Democrat, said it's one thing for Mr. Trump to get angry, but quite another to ditch the agreement.
Mr Larry Kudlow, the US President's economic adviser, said Trudeau's comments were "a betrayal" and that he had "stabbed us in the back".
What has Trump said now?
Moments after Trudeau's government released a joint statement that was said to have been agreed upon by all seven nations (The U.S., France, Britain, Canada, Japan, Italy and Germany), Trump went on Twitter to reveal his real thoughts. "Canada has objected in words, but will also do so in actions", she said, referencing the retaliatory measures Canada will impose next month.
But by ordering his representatives to back out of the communique, Mr Trump appeared to be asserting his oft-stated aim of upsetting the status quo whether by pulling out of the global climate accord or the worldwide nuclear deal with Iran or threats to scrap the North American Free Trade Agreement. "Let us be serious and worthy of our people".
The majority of Canadian exports go to the United States, making Canada uniquely vulnerable to a USA trade war.
He also said that because of Trudeau's comments, he instructed USA trade representatives to not sign the communique the G-7 leaders had agreed upon expressing the need for "free, fair, and mutually beneficial trade".