QUEBEC CITY, Quebec (Reuters) - In the end, the long charm offensive by Canadian Prime Minister Justin Trudeau to avoid the ire of U.S. President Donald Trump failed just hours after success seemed closest, with Trump raining insults as Trudeau closed what seemed like a triumphant global summit.

Besides the escalated risk of a trade war, Trump’s blistering personal attack on Trudeau poses domestic economic and political risks for the Canadian prime minister, who has stuck to a conciliatory stance in the face of U.S. threats on NAFTA and other bilateral trade cases.

“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,” Trump tweeted as he flew to a Singapore summit on North Korea.

The attack shattered any hope that Canada could avoid U.S. tariffs on steel and aluminium or renegotiate the North American Free Trade Agreement by virtue of the charm, patience or measured response it has extended to Trump since he took office.

Trudeau’s office, reeling from the abrupt Trump reversal hours after the two men had joked and smiled their way through a fractious G7 meeting, said only that Trudeau had said nothing in his news conference that he hadn’t said before.

“Canadians are polite, we’re reasonable, but we also will not be pushed around,” Trudeau had told reporters as he reiterated that Canada would retaliate against U.S. tariffs on steel and aluminium, adding Trump’s rationale had been insulting.

While the two men have had several seemingly congenial meetings and phone calls since Trump took office, they could not be more different in terms of policy, with Trudeau a progressive liberal, outspoken on feminism and the merits of diversity and who was close to former president Barack Obama.

U.S. President Donald Trump meets with Canada’s Prime Minister Justin Trudeau in a bilateral meeting at the G7 Summit in in Charlevoix, Quebec, Canada, June 8, 2018. REUTERS/Leah Millis

Earlier in the day, Trudeau had sniped about Trump’s late appearance at a women’s empowerment breakfast, referring to “stragglers”.

Trump’s about-face sparked dismay and anger among Canadian and American free trade advocates alike.

“To our allies: bipartisan majorities of Americans remain pro-free trade, pro-globalisation & supportive of alliances based on 70 years of shared values. Americans stand with you, even if our president doesn’t,” U.S. Republican Senator John McCain tweeted after Trump on Saturday.

Trudeau’s former foreign policy advisor, Roland Paris lashed out at the U.S. president.

“Big tough guy once he’s back on his airplane. Can’t do it in person, and knows it, which makes him feel weak. So he projects these feelings onto Trudeau and then lashes out at him,” Paris tweeted.

Trade experts who have watched Trump negotiate with tough words on Twitter before said the bark of Trump’s tweets often exceeds the bite of his policy - but that this time, Canada might struggle to respond.

“The rhetoric has far outpaced the implementation,” said Geoffrey Gertz, trade analyst with Brookings think tank in Washington. “Now we might be at a turning point ... (Canadians are) a little bit at a loss right now to figure out what to do.”

But while Trudeau’s months-long effort to reach out to U.S. politicians and business leaders at every jurisdiction and level may not have won over Trump, it may pay dividends if Trump’s attack finally spurs support from business groups or Congress.

Republicans worry the dispute with Canada could become an issue in trade-dependent farm states ahead of November congressional elections.

“There’s some movement within Congress now to rein in Trump on trade policy,” Gertz said.

During the summit, Trump had changed the photo on his Twitter page to the “family photo” taken with other G7 leaders. Somewhere over the Atlantic, minutes after attacking Trudeau, he swapped that for a photo with soldiers saluting during the national anthem.