Myths can be reassuring and misleading.

They are often, as well, easy substitutes for critical thinking among lazy writers whose gaze is permanently fixed on the present, without so much as an occasional glance at the not-so-distant past.

These truths have been on abundant, telling display over the past few weeks as Donald Trump continues to ricochet wildly like a frenetic pinball, bouncing from one petulant tirade to another.

Trump's latest spasm of idiocy wrapped in the imprimatur of the presidential seal was his primary-school-yard-like taunts over trade and tariffs lobbed like diplomatic grenades at Canada - that loveable, cuddly country led by a loveable, cuddly prime minister.

In Trump's manic mind, Canada is, in fact, a sly, fiendish, duplicitous "trading partner" that has fleeced America out of good jobs and profitable business for far too long.

"Canada's brutal, Canada's really tough," Trump told an adoring crowd of cultists in Pennsylvania recently. "Because they just outsmarted our politicians for decades."

To teach America's traditionally compliant poodle to the north and other foreign runts a sharp, potentially painful lesson, Trump has threatened to slap hefty tariffs on steel and aluminium. Later, Trump offered Canada and Mexico a temporary reprieve on the proposed levies in exchange for concessions during the never-ending NAFTA re-negotiations.

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Trump's vindictive gambit was, of course, in keeping with his vindictive character. Clearly, this is a president who considers brazen threats, humiliation and extortion effective negotiating tools.

Despite the hyperbolic expressions of gob-smacking aghast by historically illiterate pundits in Canada and abroad, Canadian-American relations haven't always been lovey-dovey, and Trump's not the first US president to use profanity, threats, humiliation and extortion to try to fashion his preferred way with oh-so-loveable, but, at times, recalcitrant Canada.

John F Kennedy was an attractive, charming bully who couldn't abide the sight of Canada's then Conservative prime minister, John Diefenbaker. Tit-for-tat, Diefenbaker wasn't a big fan of America's "young pup" president.

In any event, Kennedy expected the provincial Diefenbaker to do what he was, in effect, ordered to do when the US wanted to station a slew of nuclear-tipped anti-aircraft missiles in Canada.

In the face of anti-nuclear protests at home, Diefenbaker demurred and ultimately said no. Kennedy didn't forgive or forget Diefenbaker's insolence. After a terse White House meeting with Diefenbaker in early 1961, Kennedy told his brother, Robert: "I don't want to see that boring son-of-a-b**ch again."

Diefenbaker's view of Kennedy was even less charitable. "He's a hothead. He's a fool - too young, too brash, too inexperienced, and a boastful son of a b**ch!"

Fast forward to April 1965: Kennedy was dead, murdered by an assassin's bullets. Lyndon Johnson, a decidedly less attractive, less charming bully was president, consumed by a disastrous imperialist war in Vietnam that the US was losing.

Lester B Pearson, a bow-tie wearing former career diplomat and Noble Peace Prize winner turned Liberal prime minister, made a speech at Temple University, where he suggested the US pause the lethal, incessant bombing of North Vietnam and seek a solution by talking.

Enraged by Pearson's audacity and temerity, Johnson summoned Pearson to Camp David the following day where he administered a verbal rod to the short, soft-spoken Canadian.

Johnson, who stirred outrage after being pictured picking up his beagles by their ears, almost did the same with Pearson, opting instead to haul the diminutive prime minister up by his shirt lapels.

"Don't you come into my living room and piss on my carpet," the towering Johnson barked at the mortified Pearson.

Pearson got Johnson's profane, brutish message. He never made another speech at another American university to advise, suggest or imply that Johnson should stop the bombing and killing and to give peace a chance.

Pearson was succeeded by Pierre Elliott Trudeau. Johnson was succeeded by Richard Nixon. Trudeau didn't like Nixon. Nixon despised Trudeau.

Trudeau's inspired description about the nature and state of relations between the two countries may have triggered a pathologically thin-skinned Nixon.

"Living next to you is in some ways like sleeping with an elephant. No matter how friendly or temperate the beast, one is affected by every twitch and grunt," Trudeau said in Ottawa in 1969.

The depth of the US president's seething enmity towards Trudeau was revealed in 1971 when Nixon was captured on his no longer secret Oval Office tape recorder calling Canada's cerebral, Jesuit-trained prime minister, "an a**hole."

Trudeau's retort was as dismissive as it was scathing: "I've been called worse things by better people." Ouch.

The pair met at the White House in 1971. After the visit, Nixon turned to his chief of staff, H R Haldeman and, with his signature coarseness, said: "That Trudeau, he's a clever son of a b**ch."

Nixon wasn't done with the "pompous egghead" just yet. He hatched a plan with his henchman, Haldeman, to plant an embarrassing story about the Canadian prime minister with the high-profile and widely-syndicated muckraking columnist, Jack Anderson.

"You've got to put it to these people for kicking the US around after what we did for that lousy son of a bitch. Give it to somebody around here," Nixon told Haldeman.

That was almost 50 years ago. But the presidential threats and petty desire to get even with "lousy" Canadian politicians who are "kicking the US around" is a virtual word-for-word facsimile of Donald Trump's angry, barely coherent rhetoric today.

Trump is simply saying and doing in public what his predecessors said and did in private when they got miffed with what they were convinced Canada was saying and doing - publicly or privately - to harm America's "national interest."

So, note to revisionist pundits pining for the halcyon days of Canadian-American ties: Trump isn't the first obscene and ugly American president, and he certainly won't be the last.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial stance.