Hours after the USA president left the G7 summit in Quebec on Saturday, he launched insults at the prime minister, calling him "very dishonest and weak".
Mr Trump's strained relationship with the rest of the G7 was in evidence on Saturday when he arrived late for the opening session, with Mr Trudeau addressing a gathering that included an empty chair where the president was meant to be.
President Trump concluded his G7 meetings, declaring the US has been taken advantage of for decades on trade, and assured that all of the involved countries are much more committed to fair trade with America.
President Trump took issue with Trudeau's remarks on trade between the US and Canada, in which the prime minister warned his government would take retaliatory measures if new tariffs were introduced.
Trump said on Twitter that he would not sign the communique, calling Trudeau "very dishonest & weak" for his trade criticism. That was a part of Trudeau's mistake.
Canada's foreign minister Chrystia Freeland said her country "does not conduct its diplomacy through ad hominem attacks".
The chancellor also addressed concerns that Trump would hit back by implementing tariffs on German vehicles, saying, "First of all, we'll try and see if we can prevent this".
Trudeau said Canada planned to retaliate after the Trump administration announced tariffs last month that will be coming as of July 1. -Canada border. He said unleashing retaliatory measures "is not something I relish doing" but that he wouldn't hesitate to do so because "I will always protect Canadian workers and Canadian interests". Our Tariffs are in response to his of 270% on dairy!
And no wonder, as it appeared to depict the defining confrontation of the weekend's Group of Seven summit, the divide between U.S. President Donald Trump and the rest of the G7 leaders over Mr. Trump's unilateral tariffs on imported steel and aluminum.
"The United States has been taken advantage of for decades and decades", Trump said.
"We have done just that at this summit, registering our deep disappointment at the unjustified decision by the U.S. to apply tariffs to European Union steel and aluminium imports".
Sunday a Democratic Representative from IL surprisingly sided with President Donald Trump in the White House's ongoing war of words over tariffs with Canadian Prime Minister Justin Trudeau.