Ahead of the meeting, Trump already set a hostile tone on his Twitter profile, lashing out against Canadian Prime Minister Justin Trudeau over fees on dairy products, calling him indignant, in addition to criticising unfair tariff barriers.
"And that's what bad-faith Justin Trudeau did with that stunt press conference", said Navarro told "Fox News Sunday".
Trump negotiated in good faith on the communique agreed by the other members of the G7, only to have Trudeau criticize US policy after he left, Kudlow said.
Trump breaks with G7 joint statement
But in a tweet after flying out of Canada, the USA president showed he was in no mood to back down in any trade dispute . Macron launched the offensive on Thursday at a joint news conference with Canadian Prime Minister Justin Trudeau .
Trump clashed with Trudeau after the prime minister said Canada would enact retaliatory tariffs in response to U.S. tariffs on steel and aluminum imports.
Other photos taken of the discussion were soon released, by the White House and the offices of other leaders.
"He made an error", Kudlow said on CNN's "State of the Union".
Canadian Foreign Affairs Minister Chrystia Freeland, according to The Hill, responded to the backlash from the White House saying "Canada does not believe that ad hominem attacks are a particularly appropriate or useful way to conduct our relations with other countries".
Trump missed Trudeau's introductory statement at the meeting and entered the room while council co-chair Isabelle Hudon, who is Canada's ambassador to France, was speaking.
Asked if she was concerned that Trump could retaliate against European Union counter-measures by imposing tariffs on cars, Merkel said: "First of all, we'll try and see if we can prevent this".
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Trudeau said the communique has "strong commitments about the actions we are going to take". She also said that Europe will not let itself be "deceived" again.
A few hours earlier, Trudeau had told reporters that all seven leaders had come together to sign the joint declaration.
On Sunday, Kudlow said that the president had "no alternative" than to pull out of the communique after Trudeau "betrayed Trump and betrayed the whole G7" by "attacking" Mr. Trump.
Trudeau had announced that the G7 members - Canada, France, Germany, Italy, Japan, the United Kingdom and the US - had agreed upon a joint communiqué, or formal statement, after a hard week on trade issues.
The response from Mr Macron suggests an end to what observers had noted was a budding "bromance" between the French president and Mr Trump.
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