Several hours after Trump left the summit in Canada on Saturday, he revoked his support for a joint statement the US had previously agreed to.
Trump called Trudeau "very dishonest and weak" on Twitter on Saturday and then sent Kudlow and trade adviser Peter Navarro to hammer the message home on Sunday morning news shows in an extraordinary assault on a close USA ally and neighbor.
Trump described Justin Trudeau conduct in Saturday's meeting as "meek and mild" behind closed doors.
The top trading partners of the United States are upset over recent imposition of a 25 per cent tariff on import of steel and 15 per cent on aluminium. "Canadians - we're polite, we're reasonable - but we also will not be pushed around".
If the recent plummeting of the US-China relations on trade is any indicator, Trump means business and it won't be far that India will be whiplashed too for its tariffs. "The Prime Minister said nothing he hasn't said before - both in public, and in private conversations with the president".
Trump and Kim are set to meet tomorrow at the Capella Hotel on Sentosa for talks which could see North Korea dismantle its nuclear arsenal in return for economic help and security guarantees.
How did Trump respond to all of this? "To our allies: bipartisan majorities of Americans remain pro-free trade, pro-globalisation & supportive of alliances based on 70 years of shared values". "It's that much more important that Europe stands together and defends its interests even more aggressively".
"There remain good reasons to fight for the transatlantic partnership", she said, adding that the current round of trade tariffs that the USA and European Union have imposed on each other did not signal the end of a partnership.
Germany also said it will stand by the jointly agreed communique.
Copies that begin "We, the Leaders of the G-7." were distributed in the press room stamped "Approved".
Isolated Kim Jong Un takes big gamble leaving home for Trump summit
But if not, "at least we'll have met each other, we'll have seen each other; hopefully, we'll have liked each other". I mean, I try to eat and eat and eat, but he is just getting too fat too fast.
"Very dishonest [and] weak", Trump tweeted. A senior administration official told the reporter that Mr Trump had been angered by Mr Trudeau's comments.
"I have instructed our US Reps not to endorse the Communique as we look at Tariffs on automobiles flooding the US Market!"
But Mr Trump insisted it would be an "asset" to have Vladimir Putin back at the summit table.
A German government spokesman also said that Berlin stands by the jointly agreed G7 communique in which leaders underlined the crucial role of a rules-based worldwide trading system and promised to fight protectionism.
The July crude contract was down two cents to US$65.72 per barrel and the July natural gas contract was up five cents to US$2.94 per mmBTU. And so we are talking to many countries.
"We need Russian Federation for disarmament talks" and for discussions about both Ukraine and Syria, Merkel said.
"We have a very good relationship with President Trump, we work with President Trump, the United Kingdom has a very good relationship with the U.S.", she said.
"It will certainly be an exciting day and I know that Kim Jong-un will work very hard to do something that has rarely been done before. create peace and great prosperity for his land".
"It's actually not a real surprise".
"The European Union will continue to stand up for an worldwide, rules-based, multilateral system", Schinas said.