Canadians are mostly relieved that Nafta 2.0, now called the U.S.M.C.A., was signed and that Mr. Trump’s threats of economic ruination for their country are over. But if he thinks the argument with his neighbor is all patched up, then he is terribly wrong.

“The president insulted our country, our prime minister and even our chief negotiator,” said Frank McKenna, a former premier of New Brunswick and a former Canadian ambassador to the United States.

“He not only used rude language, he threatened our economic welfare,” Mr. McKenna said. “And he seemed to do it with great glee. People won’t forget that. I think that’s now deep in our psyche — the way we were treated by this president.”

The months of negotiations over the North American Free Trade Agreement delivered increasing shocks to Canadians, who have long thought of themselves as the beloved — if somewhat ignored — little sibling of their superpower neighbor.

[Canadians on New Trade Deal: ‘Do Not Consider the Friendship Resurrected’]

Sure, many Americans couldn’t place Canada’s capital, Ottawa, on the map or name the country’s prime minister — a hit television routine was predicated on this benign ignorance — but that was largely accepted as proof of a relationship so strong that it could be taken for granted.