(CNN) The West is in crisis after the G7 summit ended in acrimony and the United States accused host Canada of stabbing President Donald Trump in the back.

A fragile show of unity at the meeting in Quebec was blown apart with America isolated from the rest of the world's most industrialized democracies after Trump pulled support for a common communique in a showdown over his steel and aluminum tariffs.

"PM Justin Trudeau of Canada acted so meek and mild during our @G7 meetings only to give a news conference after I left saying that, 'US Tariffs were kind of insulting' and he 'will not be pushed around.' Very dishonest & weak. Our Tariffs are in response to his of 270% on dairy!' Trump tweeted from Air Force One hours after he left the summit for Singapore.

Trump had earlier accused America's allies of using the US as a "piggy bank" but branded suggestions he was dividing the world's biggest democratic economies as "fake news."

At his closing news conference after Trump left the summit early, Canadian Prime Minister Justin Trudeau warned that his country would respond to Trump's trade moves, said the President's argument that its trade policy threatened US national security was "insulting," and added, "we will not be pushed around."

But the President's top economic adviser Larry Kudlow said on CNN's "State of the Union" Sunday that Trudeau had pulled off an "amateur" and "sophomoric political stunt," and said it was motivated by domestic political considerations. Critics often make similar accusations about Trump's own foreign policy approach.

Kudlow said Trudeau "really kind of stabbed us in the back" and said Trump could not "let a Canadian prime minister push him around" ahead of his summit on Tuesday with North Korean leader Kim Jong Un.

The communique meltdown followed a summit that highlighted ideological and political divisions between Trump and Western allies that fueled fears that the most successful alliance in history is eroding.

"What worries me most however is the fact that the rules based international order is being challenged, quite surprisingly not by the usual suspects but by its main architect and guarantor, the US," Donald Tusk, the president of the European Council, said in Quebec before the spat over the communique.

When Trump was asked at his own press conference in Quebec about frustrations flying between he and other leaders like French President Emmanuel Macron and Canada's Prime Minister Justin Trudeau, he reacted angrily.

"I would say the level of relationship is a 10. We have a great relationship. Angela (Merkel) and Emmanuel (Macron), Justin (Trudeau). I would say the relationship is a 10," Trump said.

His anger was revealing of his operating method as President, his attitude towards America's traditional foreign policy positions and his skill in using theatrical moments on the world stage to send a strong message to his loyal voters back home.

Trump's hyperbolic praise for a summit that was evidently discordant shows his refusal to allow any venture in which he is involved to be portrayed as anything other than a roaring success.

It's far from the first time Trump has created an alternative reality that serves his political narrative.

The President's comments also show how he views international diplomacy through the prism of personal connections with other leaders.

This is a holdover from his days as a deal closing real estate executive. It also hints at his view that lavish receptions he has received in places like China and Saudi Arabia are signs of unusual respect for him personally, and thus, show US ties with such states have never been better.

Trump's critics argue he is fixated on optics and risks falling prey to foreign states who use personal flattery as a way to get what they want from him on more meaningful issues.

So while Macron, who winked at Trump when he turned up late for breakfast Saturday, and Trudeau and British Prime Minister Theresa May all may have been cordial towards him, that doesn't mean that they are not frustrated and perplexed at the same time.

One senior European diplomat rejected Trump's 10-out-of-10 assessment.

"He must mean there are 10 things on which we totally disagree. Or like the title of the movie, '10 Things I Hate About You,'" the diplomat told CNN's Michelle Kosinski.

G6+1

At their closing press conferences, Trump's counterparts made clear that they would not be intimidated by his confrontational approach to diplomacy.

Macron pointed out that the purpose of the G7 was to agree on common approaches to issues facing industrialized nations and said the "spirit of cooperation was stronger" at the meeting.

But he also made comments that could be taken as a veiled critique of Trump's approach to diplomacy.

"The philosophy is that no one wins against the others. When you enter into the discussion wanting to win, that's just a narcissistic position that is wrong," he said. "There's no winner. There's only losers if you adopt that strategy."

Trudeau said he told Trump that asking Russia to rejoin the group was "not something we are even remotely looking at" after the US President has suggested reversing Moscow's expulsion over its annexation of Crimea.

But May, who wants to conclude a bilateral trade deal with Trump when Britain leaves the EU, was more conciliatory, saying she had a "very good relationship" with him and that he was right to leave early to prepare for his summit with North Korea.

In the days before the summit, European leaders had made no secret of the fact that there were fundamental disagreements with Trump, leading some observers to dub the summit the G6+1.

"The American President may not mind being isolated, but neither do we mind signing a 6 country agreement if need be. Because these 6 countries represent values, they represent an economic market which has the weight of history behind it and which is now a true international force," Macron, who sources said also had a difficult call with Trump, tweeted on Thursday.

The American President may not mind being isolated, but neither do we mind signing a 6 country agreement if need be. Because these 6 countries represent values, they represent an economic market which has the weight of history behind it and which is now a true international force https://t.co/UA86fcjozs — Emmanuel Macron (@EmmanuelMacron) June 7, 2018

Trudeau and Trump also had an acrimonious exchange over the phone over his decision to impose steel and aluminum tariffs on US allies, CNN has reported. And before he left for Quebec, Trump accused the European Union and Canada of treating the US "unfairly."

And Chancellor Angela Merkel has made clear her disquiet with Trump's policies, arguing that Germany may no longer be able to rely on its US ally.

Her spokesman Steffen Seibert tweeted a picture that seemed to capture the mood of the summit.

Zweiter Tag des #G7-Gipfels in Kanada: Beratungen am Rande der offiziellen Tagesordnung #G7Charlevoix pic.twitter.com/5GiGF6zTHr — Steffen Seibert (@RegSprecher) June 9, 2018

Merkel, hands on a table, is leaning over the President who, seated, looks defiant, with his arms crossed, with national security adviser John Bolton peering over his shoulder.

Macron is also engaging Trump -- while Japanese Prime Minister Shinzo Abe is standing with arms folded and with a resigned look on his face.

Another view, tweeted by White House social media director Dan Scavino shows the same exchange but in a less tense moment, with some officials grinning.

Canada also released pictures showing intense negotiations. Photos only show snapshots of individual moments, but it appeared that different nations were releasing pictures that supported their own versions of the narrative.

A look at negotiations, from behind the scenes at the #G7Charlevoix Summit. pic.twitter.com/2LdJAgt6fE — Dan Scavino Jr. (@Scavino45) June 9, 2018

It's about more than personalities

At their root, tensions between Trump and fellow leaders run deeper than personality.

In European capitals, officials complain that the US President's populist nationalism and economic sovereignty arguments reject values that have bolstered the West since World War II.

There have been tensions and trade spats before. In 2003, France and Germany broke with the United States in a bitter dispute over the US invasion of Iraq. But the West has never been so divided over ideology.

And no US President has been so solicitous to the West's foes, like Russian President Vladimir Putin and China's President Xi Jinping, and treated America's partners as adversaries.