CNN senior White House correspondent Jim Acosta attempted to give President Trump a history lesson Wednesday, but failed miserably after he falsely attacked the Commander-in-Chief's reference to the British invasion of the United States.
German Chancellor Angela Merkel said she expected "difficult discussions" at the summit.
Trump is scheduled to head to Charlevoix, Quebec, Canada for the G7 meeting on Friday to sit down with the leaders of the US's closest allies.
Macron tellingly said that he would have Canada's back too at the summit and said he would work with Trudeau to persuade Trump to "find a more normal path on trade topics".
The White House declined to comment and the National Security Council did not immediately return a CNN request for comment.
The French presidency official said that if a final communique were issued, France would insist it mentioned the Paris accord on climate change that Trump withdrew from past year. "The president is at ease with all of these tough issues".
In what's been seen a jab at Mr Trump, he added: "Nobody is forever". "The impact on Canada and ultimately on workers in the US won't be a laughing matter".
Kudlow said allies should understand that Trump "will do what is necessary to protect the US, its businesses and its workforce", adding that Trump "has always said, and I agree, tariffs are a tool in that effort".More news: North Korea, U.S. fine-tune details for June 12 Singapore summit
Last week, the Trump administration unveiled punishing tariffs on imports of steel and aluminum from the EU, Canada and Japan, among others.
Trump bragged at a fundraising speech later that month that he made up facts in a meeting with Trudeau, claiming the USA runs a trade deficit with its biggest ally. Macron, who appeared to have built a warm relationship, said the "G6" leaders would not spark a fight at the summit.
"The global trade system is broken and President Trump is trying to fix it".
Canada's Trudeau also slammed the tariffs after they were announced, calling them "totally unacceptable". On the agenda for the two-day summit will be economic growth, employment, gender equality, climate change and world peace. Kudlow was vague on whether the summit will produce a joint decision or a clear outcome on trade or other issues, saying "let them meet first". "Look forward to seeing them tomorrow".
The increasingly critical tone from allies is a shift after leaders spent the past year and a half seeking to woo and cajole the American president. If Trump really is accusing them of historical crimes they didn't even have the ability to commit, I don't have much hope that we will avoid the certain economic catastrophe that we're barreling towards next month.
Trump will come face-to-face at the gathering in Charlevoix, Quebec, with world leaders whose views do not chime with his on a range of issues from trade to the environment as well as Iran and the construction of a new United States embassy in Jerusalem. Even Republicans were left to wonder, "When has Canada ever posed a national security threat to the United States?"
"They want to punish us, but. the Americans will pay a big price for the product they want from us", said Regis Gauthier, shortly after he chatted with Trudeau while the prime minister greeted people at the food court.
"This is deeply offensive to Canadians", Alden said.
The United States is reportedly preparing to unleash another round of tariffs on Canada as retribution for its Can$16.6 billion (US$12.9 billion) in tariffs on USA goods.