Canadian Prime Minister Justin Trudeau, left, and President Trump in happier times. (Michael Sohn/AP)
Stephen Marche lives in Toronto. His most recent book is "The Unmade Bed: The Messy Truth About Men and Women in the Twenty-First Century."

Being close to the United States is sort of like having the world’s lousiest friend. In the ordinary course of business, it belittles you, ignores you, takes you for granted. When it needs you, when it’s in the middle of an emergency, it shows up expecting you to drop everything. Then, the moment it has what it wants, it forgets you ever existed.

Canadians are used to dealing with an unpredictable and occasionally insane neighbor to the south, but Thursday’s announcement that the United States would impose tariffs on steel and aluminum imported from Canada, Mexico and the European Union was a true friendship dealbreaker. American foreign policy is becoming a study in how to lose friends and alienate people, how to turn ancient allegiances into fraught conflicts for the vaguest of possible motivations.

U.S. callousness and intransigence are hardly new to Canadians or to Canadian policymakers. In 1969, Justin Trudeau’s father, Pierre, famously declared in a speech to the Washington Press Club that living next to the United States was “like sleeping with an elephant.” He did not mention, because he didn’t need to, that the elephant he was thinking of wasn’t the smart kind, the kind that has conversations and celebrates births and buries its dead. He meant the big, dumb kind that rolls around in the filth and doesn’t care whom it tramples.

Despite Canada’s long history of close vigilance and deep anxiety when it comes to the United States, it is highly unusual for a sitting prime minister to take shots, even the mildest ones, even off the record, against its neighbor. Canadian Prime Minister Justin Trudeau’s public comments  Thursday were almost without precedent.

“For 150 years, Canada has been America’s most steadfast ally,” Trudeau began, before pointedly citing his country’s recent sacrifices of blood and treasure: “We came to America’s aid after 9/11.” The prime minister tried to end his statement on a positive note, but the anger remained near the surface. “We have to believe that at some point, common sense will prevail. But we see no sign of that.”

It’s not hard to read through the lines to find the real meaning in what Trudeau is saying: nothing against the United States, it’s just President Trump. He’s not anti-American. He’s anti-Trump. The question is how long that distinction can last.

The last time the Canadian government was this upset with the United States, America was in a civil war (maybe we should start calling it the First Civil War), and Canada wasn’t even a country yet. The Union Navy had seized a British vessel, the Trent, containing Confederate diplomats, and Abraham Lincoln had to tell his secretary of state, William Seward, to fight “one war at a time.” Canadian Confederation was, in large measure, a response to the threat posed by the newly militarized and unpredictable U.S. body politic.

The breakdown of U.S.-Canada relations isn’t all Trump, either. U.S. faith in the country’s exceptionalism can seem general and total, and for many Canadians, it can be hard to bear. If you went to a random street corner in, say, Chicago, and asked Americans whether Canada fought in Vietnam or Afghanistan or Iraq, how many would know? So why would you fight with people who can’t remember whether you’ve fought with them?

At the news conference where he announced retaliatory tariffs, Trudeau described how a NAFTA deal-in-waiting was jettisoned by Vice President Pence. It was Pence who informed him, at the last moment, that his government wanted a “sunset” clause so that the agreement would expire after five years.

Trudeau demurred. How could he not? A sunset clause would have made the deal useless, offering no reliable guarantees for cross-border businesses. The demand for the clause was typical of the way a lousy friend operates, upping the drama, making sure the drama never ends. Pence was, of course, acting for Trump, who made the demand because he knows there will be little to no cost to him domestically for treating a long-standing ally like a schmuck. He merely reflects ingrained self-regard and indifference.

Trump isn’t known for having friends, and he obsesses over who his enemies might be. He creates enemies so that he has a way to define himself. That process has been extended from his personal life to the U.S. political system and, from there, to the international order. His base wants more enemies. And I guess they’ll take them where they can find them. It’s hard to imagine how you work yourself up to hate Canadians, but we’re living in times of great innovation.

Most Canadians still love Americans. “I want to be very clear about one thing,” Trudeau declared. “Americans remain our partners, friends and allies.” For how long? Self-interest is going to start taking over at some point. Fewer tariffs on China, weak sanctions on Russia and new tariffs and new threats of sanctions on us? Trump in particular, and the United States in general, respect you only if you’re an enemy. So why be a friend?