The U.S.-Canada relationship has had its ups and downs over the decades.

The rough patches were often linked to Canada not knuckling under to the U.S. over such things as its blockade of Cuba or taking in American war resisters.

As Montreal writer Yves Engler has pointed out in his books, Canada has usually gone along with U.S. imperialist ambitions, perhaps most notably under former prime minister Lester B. Pearson.

But now, it appears as though Canada has reached an impasse with the Trump administration over tariffs, which could come to a head this week.

Trump has many reasons to loathe Canada these days. Here are just five of them.

1. Naomi Klein

Some of Trump's most creative critics in America have come from Canada, including author Naomi Klein.

Not long after Trump moved into the White House, the leftist icon penned No Is Not Enough: Resisting Trump's Shock Politics and Winning the World We Need.

Unlike many of his other critics who zeroed in on politics, Klein urged readers to undermine Trump's business empire.

She appeared in the media recommending boycotts of Trump hotels and companies that carried Ivanka Trump's products.

The resulting public pressure led the First Daughter to shut down her fashion brand.

In Toronto, the Trump name was dropped from a hotel after celebrities shunned the building during the city's glamorous film festival.

Meanwhile in Vancouver, Mayor Gregor Robertson has asked the Holborn Group to change the name of the Trump International Hotel & Tower.

Most of the time when this property is in the news, it's in connection with political demonstrations against the U.S. president.

Nobody has played a more important role than Naomi Klein in jamming the Trump brand.

Trump surely knows that his name has become poisonous to many Canadians.

In fact, a survey on this website indicated that a significant number are even boycotting visiting the United States as long as he remains president. More than three-quarters stated that they've stopped any personal travel to America until he leaves office.

https://twitter.com/JimCarrey/status/1032298710703562753

2. Jim Carrey 

Another frequent and creative critic of Trump has been Ontario-born actor Jim Carrey.

His Twitter account features a parade of his cartoons savaging the president and his enablers.

Carrey's illustrations usually include a shout-out to his fans to register to vote to get rid of the Mango Mussolini.

https://twitter.com/JimCarrey/status/1032770337161662464

Trump haters can take comfort in Ace Ventura's dedication to the case.

https://twitter.com/JimCarrey/status/1032049342981464064

Carrey has become a problem for Trump because he has 17.9 million followers on Twitter. His images are reaching large numbers of people.

3. Tommy Chong

Yes, the old Edmonton-born stoner who sharpened his comedy chops in Vancouver has morphed into another devastating Canadian critic of the Donald.

Chong's fan base includes libertarian cannabis users who mistrust the U.S. government, which overlaps with part of the Trump base.

So even though Chong may seem like yesterday's news to those who don't smoke weed, his constant needling of the president over Twitter has become a political problem for Republicans.

https://twitter.com/tommychong/status/1034215253792313344

Chong laces his relentless condemnations with humour, constantly referring to what it's going to be like for Trump when he goes to jail.

https://twitter.com/tommychong/status/1034213327226863616

Of course, Chong knows all about the crowbar hotel. He served time after being railroaded for his love of all things cannabis.

https://twitter.com/tommychong/status/1033437854523899904

4. Samantha Bee

The Toronto-born comedian, political commentator, television host, and relentless Trump mocker cracked Time magazine's list of the 100 most influential people in the world in 2017.

After 12 years with The Daily Show, she launched Full Frontal with Samantha Bee in 2016, becoming the first woman to host a late-night satirical news show in America.

Bee's greatest sin in the eyes of the Trump family was calling Ivanka a "feckless cunt" for not publicly resisting her pop's racist immigration policies.

"Put on something tight and low-cut and tell your father to fuckin' stop it," Bee declared.

The reaction was intense and Bee subsequently apologized.

Trump, of course, gleefully called for her to be fired.

https://twitter.com/realDonaldTrump/status/1002508937445478402

Of course, there is no shortage of American celebrities who've also attracted Trump's ire, including Meryl Streep and Robert De Niro.

But the Canadians have been among the most damning, as well as the most imaginative in responding to the Cheeto-In-Chief.

Whereas De Niro simply says "Fuck Trump", Canadian celebrities are using political cartoons, jail-laced humour, and consumer boycotts to drive home their point.

For a thin-skinned president, this likely hasn't gone unnoticed.

5. Justin Trudeau

Canada's pretty-boy prime minister is everything that Trump isn't: young, good-looking, fluently bilingual, and physically fit.

It's also worth noting that Trudeau isn't a murderous dictator. He's a democrat who will willingly cede power should he ever be voted out of office.

That's likely another negative mark in the eyes of Trump, who admires tough guys like Kim Jong-un, Vladimir Putin, and the Crown Prince of Saudi Arabia, Mohammed bin Salman.

Trump turned on Trudeau immediately after he and other G7 leaders rejected the idea of inviting Putin into their club.

A new book by U.S. investigative journalist Craig Unger exposes the deep connections between Trump and Putin and his cronies.

House of Trump, House of Putin: The Untold Story of Donald Trump and the Russian Mafia raises serious questions about how the president's three-decade business relationship with Russian oligarchs and their minions in America have affected U.S. foreign and trade policies.

Trudeau's loyalties have been with Ukrainians who are resisting Putin's incursions and the seizure of Crimea. It plays well with Canada's large population of people of Ukrainian ancestry.

Trudeau even appointed a foreign minister of Ukrainian descent, Chrystia Freeland, who's despised by the Kremlin.

It's easy to see why Trudeau is on the outs with Putin's man in the White House.

If Trump ends up imposing 25 percent tariffs on Canadian-made automobiles, Unger's book offers important insights into understanding the president's motivations with regard to international diplomacy.

The conventional wisdom in Ottawa used to be that Trudeau's staff were managing the Canada-U.S. relationship well by cultivating the support of Ivanka Trump and her husband, Jared Kushner.

But a recent iPolitics column by Susan Delacourt pointed out that the influence of this duo has diminished significantly within the White House.

That's creating problems for the Canadian government on the trade file.

Again, readers of House of Trump, House of Putin can only conclude that it's Trudeau's position with regard to Russia—and his appointment of Freeland as the foreign affairs minister—that has ignited Trump's fury.

If Tommy Chong is correct with his predictions Trump will end up in jail, then that problem will solve itself in due course.

In the meantime, there's always Mike Pence waiting in the presidential bullpen. And in the past, the fundamentalist Christian crusader has been a keen supporter of an open trading relationship with Canada.

Stay calm. Presidents come and go. This one might not even be in office a year from now.