The United States and Canada have entered into uncharted territory.
The longtime allies and economic partners, who have enjoyed free trade for decades, are now in an escalating trade war with no clear off ramp.
And for Prime Minister Mark Carney, the late night decision to suspend talks with President Donald Trump and to retaliate instead of agreeing to a deal that seemed in reach will be a significant political test.
He is one of the first world leaders to walk away from the negotiating table with the White House – and the outcome will be closely watched.
Both sides have blamed last-minute changes for torpedoing the tentative deal, with Carney saying the US “asked too much” and “offered too little”.
Carney’s decision will challenge the appetite among Canadians to accept some economic pain as Ottawa pushes for more US concessions.
After rejecting Trump’s high pressure tactics, and in choosing to hit back against the latest duties, Carney will need to convince Canadians that the economic pain is worth the cost of standing up to the Trump administration in search of a better agreement in the long run.
In remarks on Saturday, he said “we take this step confident this is in the best interest of Canada” and accused the US of a “power play” by seeking eleventh-hour changes.
Asked by a reporter whether the US and Canada were locked in a trade war, he replied: “You’re at war when you’re attacked – we got attacked.”
Switching to French, he said the spiralling trade dispute “wasn’t our choice”, adding: “Canada is strong, Canada is ready, Canada is united.”
There is no doubt this will cause pain on both sides of the border, with business facing more pressure from US duties and Canadian counter-tariffs.
Canada sends about 70% of its exports to the US, and the country is the top trading partner for a number of US states, with Michigan, Kentucky, Indiana and Ohio among the most exposed.
Carney came to power with a call for “elbows up” – an ice-hockey term for an aggressive approach – vowing to fight for Canada in the face of a Trump administration keen to exert economic pressure for its America First agenda.
Many Canadians have told pollsters that they are willing to fight.
A recent survey by Abacus Data suggested that around 36% of Canadians would support retaliating to US tariffs, while a Leger poll indicated that 56% of Canadians want the federal government to take a hard line and make no more concessions.
Canadians frustrated with the US tariffs have already chosen to avoid travelling there. The boycott has meant a loss of about C$3.3bn ($2.35bn; £1.75bn) in travel revenue for the US last year.
A decision by most provinces to remove US alcohol from store shelves has hammered that sector.
Based on US government trade data, US wine exports to Canada fell 78% year over year, a $357m loss in export value. The US distillers association reported similar numbers – saying provincial bans have caused exports of American spirits to drop by more than 70%.
The ban quickly became a point of frustration for the Trump administration.
Canada’s prime minister will also need to convince the provinces who have been less affected by the US trade dispute so far that walking away is a risk worth taking.
He briefed them on Saturday on the current state of affairs, and for now, they are showing a united front.
British Columbia Premier David Eby said he was committed to the “national project we are on”, while Ontario Premier Doug Ford said “we didn’t start this fight but I can assure you. we’re going to win this fight”.