Trump left the summit after breakfast Saturday to fly to Singapore to prepare for his meeting with North Korean leader Kim Jong-un.
At his closing news conference, Trudeau had repeated his prior statements that he believed the US's national-security rationale for imposing steel and aluminum tariffs was "insulting", and that Canada would impose retaliatory tariffs. Moving onto tariffs, Canada's Prime Minister Justin Trudeau denounced Trump's plan to slap hefty tariffs on steel and aluminum imports on key USA trading partners.
The demise of the fragile communique is seen as a major blow to the strength of the G7 alliance, which is made up of wealthy developed democracies that also includes Germany, Japan, France, the United Kingdom and Italy.
That was Justin Trudeau's late father, who served several terms as Canada's prime minister, starting in the late 1960s.
"We will not.sign a trade deal that expires every 5 years - that is not a trade deal", Trudeau said.
When pressed on how exactly Trudeau may have betrayed the US, Kudlow revealed that the White House was interpreting Trudeau's comments as a stunt created to threaten Trump's much-anticipated upcoming meeting with North Korean leader Kim Jong Un this week.
"He is not going to permit any show of weakness on the trip to negotiate with North Korea -" Kudlow added.
The statement, which did not mention Trump by name, appeared to come down on the president for "incoherence and inconsistency" in his snub of the communique which includes a commitment to "rules-based global trading system" and to combating protectionism.
"It is not something we relish doing, but it is something that we absolutely will because Canadians, we're polite, we're reasonable, but we also will not be pushed around", Trudeau said. American tariffs are in response to Canada's tariffs of "270% on diary" delivered by the United States, he said.
Trump also tweeted that Trudeau had acted "so meek and mild" during their meetings and that his tough talk later is "dishonest & weak".
The fight isn't just with Trudeau and Canada but with the best allies of the U.S., Democratic Senator Dianne Feinstein of California said on CNN.
Trump swiftly responded to Trudeau by upending the communiqué in a series of tweets Saturday evening.
White House trade adviser Peter Navarro went a step further, suggesting to Fox News Sunday morning that there's a "special place in hell" for the Canadian prime minister.
As a result, the USA did not participate in discussions created to tackle climate change and the removal of plastics from the world's oceans.
Kudlow said Trudeau had engaged in a "a sophomoric political stunt for domestic consumption" and should apologize.
In a separate interview on CBS's "Face the Nation", Kudlow said the Trump had a "very successful, calm, friendly, respectful bilateral" with Trudeau and that the USA won't withdraw from Nafta.
After departing from the Quebec summit for Singapore, Mr Trump tweeted that he had asked American representatives not to endorse the joint communique put out by the G7 leaders, which called for a "free, fair, and mutually beneficial trade" and the importance of fighting protectionism.