Following President Trump’s imposition of tariffs on Canada, Prime Minister Justin Trudeau made a remarkable statement that went largely unnoticed amid the turmoil.

Speaking to the press in Ottawa, Mr. Trudeau asserted, “The pretext he is providing for these tariffs today, related to fentanyl, is entirely unfounded, unjustified, and false.”

“His intention is to witness a complete collapse of the Canadian economy, as that would make it easier for him to annex us,” he added.

This narrative traces Mr. Trudeau’s shift from initially perceiving Mr. Trump’s comments about him being “governor” and Canada as the “51st state” as jests, to openly declaring that Canada’s closest ally and neighbor is attempting to economically subdue Canada to take control.

The February Calls

Mr. Trump and Mr. Trudeau engaged in talks on Feb. 3, both in the morning and afternoon, as they worked to prevent tariffs on Canadian exports.

However, those February conversations were not solely about tariffs.

The specifics of these exchanges between the two leaders, along with subsequent discussions involving top U.S. and Canadian officials, have not been previously fully disclosed. The details were shared with The New York Times on the condition of anonymity by individuals with direct knowledge of the discussions’ content, who did not wish to be named when addressing a sensitive issue.

During these calls, President Trump listed numerous complaints about the two countries’ trade relationship, including Canada’s protected dairy sector and the unfavourable conditions faced by American banks operating in Canada.

He also broached a more basic issue.

Mr. Trump informed Mr. Trudeau of his disbelief in the treaty that demarcates the border between the nations and his interest in revising the boundary. No further explanation was provided.

The border treaty in question was established in 1908 and finalized the international boundary between Canada, which was then a British dominion, and the United States.

Mr. Trump also brought up the possibility of reevaluating the shared lakes and rivers between the two countries, regulated by multiple treaties, which was a topic he had previously expressed an interest in.

Canadian officials took Mr. Trump’s comments seriously, especially since he had publicly stated his intention to bring Canada to its knees before. In a January 7th press conference, before being sworn in, Mr. Trump responded to a question by a New York Times reporter about using military force to annex Canada by saying that he would use “economic force.”

The White House did not respond to a request for comment.

During the second call on Feb. 3, Mr. Trudeau managed to secure a one-month postponement of the tariffs.

This week, the U.S. tariffs took effect without any further reprieve on Tuesday. In response, Canada imposed its own tariffs on U.S. exports, sparking a trade war between the two countries. (On Thursday, Mr. Trump suspended most of the tariffs for a month.)

Over the past few months, signs of the rift between Mr. Trump and Mr. Trudeau—and Mr. Trump’s aggressive agenda for Canada—have become more evident.

The Star, a Canadian newspaper, reported that Mr. Trump had brought up the 1908 border treaty during the early February call and had mentioned other details of the conversation. And the Financial Times reported that there are discussions in the White House about the U.S. potentially exiting a critical intelligence alliance that comprises five nations, attributing this to a senior Trump adviser.

Doubling Down

It wasn’t merely the discussions about the border and waters with Mr. Trudeau that unsettled the Canadian government.

There was persistent social media chatter referring to Canada as the “51st state” and Mr. Trudeau as “governor,” which had started to irk both the Canadian government and the public at large.

It’s possible that Mr. Trump’s statements could be mere bravado or a negotiation ploy to pressure Canada into trade or border security concessions, but the Canadian side no longer believes that to be the case.

Indeed, the realization that the Trump administration was taking a more aggressive look at the relationship—one that aligned with threats of annexation—struck during subsequent calls between key Trump officials and their Canadian counterparts.

One such call took place between Secretary of Commerce Howard Lutnick, who had not yet been confirmed by the Senate, and Canada’s finance minister, Dominic LeBlanc. The two men had been in regular communication after their meeting at Mar-a-Lago, Mr. Trump’s home and club in Florida, during Mr. Trudeau’s visit in early December.

Mr. Lutnick called Mr. LeBlanc following the Feb. 3 discussions between the leaders, conveying a jarring message: Mr. Trump had realized that the relationship between the United States and Canada was underpinned by numerous agreements and treaties that were easily abandoned.

Mr. Trump was interested in doing just that, Mr. Lutnick said.

He sought to eject Canada from an intelligence-sharing group known as the Five Eyes, which also includes Britain, Australia, and New Zealand.

There were plans to dissolve the Great Lakes agreements and conventions that exist between the two countries, regulating the management and sharing of lakes Superior, Michigan, Huron, Erie, and Ontario.

Also under review was military cooperation between the two countries, especially the North American Aerospace Defense Command.

A spokesperson for Mr. Lutnick did not respond to a request for comment. A spokesperson for Mr. LeBlanc declined to comment.

In subsequent communications between senior Canadian officials and Trump advisers, this list of potentially contentious issues resurfaced repeatedly, making it difficult for the Canadian government to dismiss these concerns.

The only calming influence has been Secretary of State Marco Rubio, who has refrained from making threats and has recently dismissed the notion that the United States is considering ending military cooperation.

However, across the political spectrum in Canada and within Canadian society, there are frayed nerves and deep concerns. Officials do not view the Trump administration’s threats as idle; they see these as a new standard for U.S.-Canada relations.

In a news conference on Thursday, a reporter asked Mr. Trudeau: “Your foreign affairs minister described all this as a psychodrama. How would you describe it?”

“Thursday,” Mr. Trudeau replied ruefully.