Canadians might be surprised by the extent to which political events in this country were shaped by the charismatic U.S. leader, famously assassinated 50 years ago this week.
Helping to elect the Pearson Liberals, for starters, who would go on to introduce a new national flag, expand the welfare state and create medicare, the old-age pension system, and the royal commission on bilingualism.
The Liberals got tactical support, with state-of-the-art polling. Diplomatic rockets rained down on their opponents. And in the heat of an election campaign, the opposition leader was invited to the White House as an honoured guest.
The perceived interference became so acute that a fuming John Diefenbaker eventually took the extraordinary step of recalling Canada's ambassador to the U.S.
That diplomatic riposte failed to stop the Diefenbaker Conservatives from disintegrating, through internal divisions and a non-confidence motion that focused specifically on relations with the U.S.
Did Kennedy play a determining role?
"I think he played a very major role in Canadian history," John English, Pearson's biographer and a one-time Liberal MP, said in an interview.
"He definitely influenced Canadian history through the 1962-63 election period. There's no doubt that his animosity to Diefenbaker made his position very difficult not only with the broader public, but within his own party."
The Kennedy-Diefenbaker relationship was born in a toxic swamp and never emerged.
Before their first meeting, the new president angered his interlocutor by twice mispronouncing his name as "Diefen-bawker." Things didn't get any sunnier with the conclusion of that first meeting, as Diefenbaker learned immediately afterward that his mother had died.
There were the pettiest slights. The two men, different in age, temperament, and world view, even managed to get under each other's skin when comparing fishing stories. They had 'son-of-a-something' nicknames for each other, too.
Then there were the more substantive differences.
Kennedy was keen to draw Canada deeper into the American sphere. Diefenbaker, who held the more traditional attachment to Britain, balked at the invitation to join the Organization of American States.
So Kennedy went right over his head and spoke directly to the Canadian people.
Bolstered by the strength of his own personal popularity in Canada, Kennedy arm-twisted Diefenbaker in a speech to the House of Commons that is otherwise remembered for the line, "Geography has made us neighbours. History has made us friends." Kennedy's blunt public push came just one day after he'd been told by his host that the idea was a no-go.
Meanwhile, the president got along swimmingly with Pearson.
Jean Chretien, who was first elected as an MP in the Liberals' victorious 1963 campaign, believes Pearson endeared himself to Kennedy with his encyclopedic knowledge of baseball.
But he's skeptical the Kennedy relationship is what won the election. Chretien said he believes the Diefenbaker government was accumulating enough political damage on its own, without help from the neighbour to the south.
In an interview, the former prime minister said the move to oust the head of the Bank of Canada, James Coyne, harmed the Conservatives more than anything Kennedy did.
"I don't think (Kennedy made the difference)," Chretien told The Canadian Press. "Mr. Diefenbaker had a lot of problems with his administration."
However, as it turned out, the Diefenbaker Tories had enough life left in them to eke out a minority in the 1962 election, then hold the Liberals to a minority in the two that followed.
It was in the first of those three elections that Pearson received an almost inconceivably rare political gift for an opposition leader: he was invited, by a popular president, to appear at the White House during a campaign.
Weeks before the election call, the Canadian opposition leader was asked to attend a White House dinner for 49 Nobel Prize winners, with virtually all the others born in the U.S. or living there.
Not only was that invitation not rescinded upon the election call — Pearson wound up getting treated to a starring role. The president held a private 20-minute meeting with the visiting Canadian politician.
And in his speech to his distinguished guests, Kennedy referred specifically to only one of them — the baseball-loving native of Newtownbrook, Ont.
"I want to welcome you to the White House," his speech began. "Mr. Lester Pearson informed me that a Canadian newspaperman said yesterday that this is the president's 'Easter egghead roll on the White House lawn.' I want to deny that!"
Then, in the next breath: "I think this is the most extraordinary collection of talent, of human knowledge, that has ever been gathered together at the White House, with the possible exception of when Thomas Jefferson dined alone."
The Tories lost nearly 100 seats a few weeks later. Their historic majority was whittled down to a 116-seat minority.
Relations soured further when Diefenbaker challenged Kennedy's handling of the Cuban missile crisis. Finally, there was the Bomarc dispute, where Diefenbaker resisted plans to store nuclear warheads in Ontario and Quebec, under NORAD auspices.
The pressure on him was unrelenting. The retiring head of NATO came to Canada during his farewell tour and accused the Canadian government of shirking its responsibilities.
Diefenbaker later suggested he'd received private assurances from Kennedy that nuclear expansion would not be necessary. The response from the State Department was swift and devastating.
In a 1963 news release, the U.S. government denied Diefenbaker's version and, in one final indignity, it said the Canadians had failed to contribute a sufficient policy for North American defence.
Existing divisions in the Diefenbaker cabinet suddenly deepened. A handful of ministers began plotting a coup against the boss. The defence minister resigned and, after the Tories were defeated in a non-confidence vote, two of his colleagues followed.
A few weeks later, the Liberals went on to win their first of five straight elections.
Meanwhile, the Liberals had a secret ally, dating back to the previous year's campaign. Kennedy's personal pollster, Lou Harris, a trailblazer in his profession, hired 500 women to make phone calls in the most extensive public-opinion research operation ever seen at that point in Canadian politics.
"They showed the campaign committee how polling was done," said Jim Coutts, who was a young campaign operative at the time and went on to serve in the Pearson-Trudeau PMOs.
"Not just (polls about) who was ahead, and who was leading… They showed us different ways to ask questions."
The American visitor went by the name Lou Smith, his mother's maiden name. Kennedy had previously forbidden his pollster from helping British Labour leader Harold Wilson. But to help Pearson — and harm Diefenbaker — he gave his consent.
Could any of this — the subterfuge, the public shaming, the diplomatic strong-arming — have been appropriate?
Even Diefenbaker's opponents at the time thought the Kennedy administration had gone too far, with its 1963 media statement. The NDP's Tommy Douglas quipped that the Americans were treating Canada like Guatemala or Cuba.
Diefenbaker, for his part, called it an "unprecedented" intrusion. As his government was going down to defeat, he told the House of Commons: "Canada is determined to remain a firm ally but that does not mean she should be a (U.S.) satellite."
Pearson's biographer agrees it was inappropriate.
"An American president should not interfere in Canadian elections," English said. "And there's no doubt that Kennedy did, and he did not treat a Canadian prime minister appropriately. I think even perhaps Lester Pearson would agree with that, in retrospect."
But did it make a difference?
Two former Pearson aides said in interviews they probably could have won without Kennedy's intervention. But those aides — Coutts and Dick O'Hagan, Pearson' onetime press secretary — agreed it helped.
"It's hard to say. It really is. Because all one is doing is sort of guessing, or making suppositions," O'Hagan said. "I think it was helpful, but not a determinant."
English cites his own family as evidence that it indeed swung votes.
He supported the Conservatives as a boy. His father had supported them his whole life, but those allegiances shifted during the spat with Kennedy on defence issues.
"I can speak personally and say it did affect votes, in my own family."
Kennedy also impacted Canadian politics in other ways, he said.
Canadians had seen their prime minister, Diefenbaker, mocked in an unflattering Newsweek profile and were looking for more flamboyant leadership. Pierre Trudeau's 1968 Liberal leadership win, he said, would "not have been possible without John Kennedy."
In the end, perhaps Diefenbaker never stood much of a chance. His principal adversary had managed to get on Kennedy's good side, even before he was president.
In 1959, Pearson had written a glowing piece in the Saturday Review about Kennedy's book, "Profiles In Courage."
"(And) nothing makes an author happier than a favourable review," English said.
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