He also says Canadians expect him to foster with Trump "a constructive, productive relationship in which we can work together, that is based on not insulting and disrespecting each other".
Presumably, as Toronto Star reporter Daniel Dale pointed out on Twitter, Kudlow was upset that Trudeau's comments could hurt Trump's chances of impressing Kim Jong Un ahead of his meeting with the North Korean dictator in Singapore this week.
"Donald Trump may think that his outrageous behavior is softening up his trading partners but it's not working with Canada", said Roland Paris, a former Trudeau adviser and professor of global affairs at University of Ottawa.
The move comes as the House of Commons unanimously agreed to an NDP motion on Monday to condemn the USA administration's "illegitimate" import duties on steel and aluminum and pledging support for supply management, the system that regulates prices and production on dairy, eggs and poultry in Canada.
Canadian Foreign Minister Chrystia Freeland responded to the White House comments by saying that Canada will retaliate to USA tariffs in a measured and reciprocal way and that Canada will always be willing to talk.
"[Trudeau] really kind of stabbed us in the back", Mr Kudlow, the director of the National Economic Council who had accompanied Mr Trump to the G7 summit said on Monday morning on CNN. "He is not going to permit any show of weakness on the trip to negotiate with North Korea".
The outburst against Trudeau, and by association the other G7 members, is only the latest incident in which Trump has clashed with America's closest allies, even as he has had warm words for autocrats like Kim and Russia's Vladimir Putin.
President Trump says a G8 that includes Russian Federation is more meaningful than a G7, blames President Obama for letting Crimea 'get away'.
USA trade officials are going further.
Queen Elizabeth Honours Joshua With OBE
I am pleased to see the Queen's Birthday honours recognise the achievements of a diverse and inspiring number of our fellow Scots. She added: "I dedicate this award to everyone in our team and to the young people that we care for".
In Ottawa, the Canadian House of Commons passed a unanimous resolution backing Trudeau that rejected "ad hominem statements by US officials, which do a disservice to bilateral relations and work against efforts to resolve this trade dispute". "They surely can not be that upset about what the prime minister said", according to a second Canadian official.
Trump was reacting to comments made by Trudeau at a press conference on Saturday in which he threatened to torpedo negotiations on a new NAFTA deal if the Americans did not remove tariffs on Canadian steel and aluminum.
- Following Trump's departure from the G7 summit, Trudeau says in a press conference that he told the US president that his steel and aluminum tariffs were "kind of insulting", that Canada "will not be pushed around" and that it would not hesitate to impose retaliatory measures.
Bruce Heyman, who was US ambassador to Canada during President Barack Obama's administration, called on Navarro in a tweet to formally apologize to Trudeau for his "insulting and inappropriate remarks".
Canada does charge a 270 percent tariff on a limited number of dairy products.
Prime Minister Justin Trudeau is getting cross-partisan support as he tries to de-escalate a looming trade war with the United States.
One of the advantages the United States has in the long-term conflict with China is that we border peaceable, friendly countries.
"When politicians fight and when leaders argue, it is always the people who suffer", said Bergen, the MP for Portage-Lisgar, adding that the government should eliminate inter-provincial trade barriers and pursue trade with Asia.
The rumor can be traced to a video of Trudeau's press conference with French President Emmanuel Macron. "He's a pathetic little man-child".
"I think any time you have this type of a public display that allows for separation between us and our allies, that's not a healthy thing", Rounds said.