Last Friday, Trump - feeling slighted by Trudeau, who took a tough stance toward US tariffs by saying he wouldn't tolerate being "pushed around" - launched an attack via Twitter, calling the leader "dishonest" and "weak".
President Trump's trade adviser Peter Navarro said Tuesday he regretted the language he used when he responded to Canadian Prime Minister Justin Trudeau's retaliatory tariff announcement following the G-7 Summit.
"My mission was to send a strong signal of strength", Navarro said at the event, the Journal reported.
"That's unconscionable", Heyman said."Anybody who represents the United States of America from the White House using that kind of language with any world leader of any type, I think is uncalled for".
"And that's what bad faith Justin Trudeau did with that stunt press conference", he added Sunday, noting his comments came "right from Air Force One".
"I have a good relationship with Justin Trudeau, I really did", Trump said.
Also on Sunday, Trump's economic advisor Larry Kudlow told CNN that Trudeau "stabbed us in the back".
In striking such a hostile tone against one of the oldest and closest US allies, Navarro said Tuesday he was emboldened to send a "strong signal of strength" on the eve of the landmark summit between Trump and North Korean leader Kim Jong Un.
Mr Trump revoked his administration's support for the G-7 communique after Mr Trudeau's news conference.
"The president, coming late, stands before the cameras and says, "Why don't we add Russian Federation to the group".
On Trump's handling of trade - where the populist president has taken major steps to enact his economic nationalist agenda - almost 80 percent of Republican voters said they approve of trade actions thus far.
"Actually, we were just talking - the whole group - about something unrelated to everything, very friendly", Mr Trump said. "They don't take our farm products", Mr Trump complained at the news conference.
Margaret Wente: Donald Trump has finally made us mad. We have a big trade deficit with Canada.
Canada is the U.S.'s largest trading partner, and the USA economy would struggle to make up for Canada's absence, Heyman noted.
And it concludes with a direct shot at Trump, calling on the House to "reject disparaging and ad hominem statements by US officials which do a disservice to bilateral relations and work against efforts to resolve this trade dispute".