Even for those who did not and never would dream of voting for the Liberal Party, 1968 was a spring to remember.
The country was just a generation past the fusty Mackenzie King, and suddenly Canadian politics were exciting and exhilarating, and it all had to do with that new guy, Pierre Trudeau.
Trudeau was lucky; the times were made for him. The country was still bathed in the pleasure of the previous year's centennial celebrations, particularly Expo 67. The mood had persuaded people that it was right and proper to be Canadian and to be proud of it.
Giddy though it was, the lingering centennial spirit would not by itself have made Pierre Trudeau prime minister. Instead, what paved the way for his victory in the Liberal leadership convention that April was an explosion of Quebec nationalism that put the very existence of the country in peril.
John Gray has worked for a number of Canadian newspapers, including more than 20 years with the Globe and Mail, where he served as Ottawa bureau chief, national editor, foreign editor, foreign correspondent and national correspondent.
Nationalism itself was not new but it was suddenly enjoying a level of acceptance that it never previously had. And it was just weeks before that 1968 Liberal leadership convention that prime minister Lester Pearson anointed Trudeau as the federal and federalist standard bearer.
At a federal-provincial conference — against Quebec's increasingly nationalist premier Daniel Johnson, with a national television audience watching — the virtually unknown Trudeau had to argue the case for a united Canada, and he did it brilliantly.
Quite suddenly Trudeau was a national figure, and his performance against Johnson became the springboard for his Liberal leadership campaign.
For Canada, the sudden appearance of the instant hero was a shock.
Lester Pearson had been popular; after all his government had given the country its own flag, medicare and much more, and Pearson, the gentle diplomat, had won the Nobel Peace prize.
But Trudeau and Pearson came from clearly different worlds and different ages.
Trudeau's campaign speeches became thoughtful disquisitions, he flirted publicly with beautiful young women, he stared down a howling mob that was hurling bottles at him during Montreal's St. Jean Baptiste Day parade.
Trudeau was sexy. But Canadian politics was not like that. Nobody ever said that Lester Pearson was sexy.
Today's Liberal champion, Justin Trudeau, has not been so lucky. He arrived with a name in which he takes pride, but which obviously makes it hard for him to distinguish himself.
In that 1968 campaign if you were to ask almost anyone with even a modest interest in politics what Pierre Trudeau stood for, the answer would be quick and certain: bilingualism, a just society (whatever that meant), and a strong, united Canada, which usually implied keeping Quebec in its place.
For the father, the identification was clear enough. For the son, the unfair temptation has been to say that he has good hair.
The French fact
The 1968 convention also signalled a change of generations.
Until then there had been a straight line of influence from Mackenzie King and Louis St. Laurent, but suddenly the Liberal cabinet heavyweights were gone or at least eased aside: Paul Martin, Robert Winters, Mitchell Sharp, Paul Hellyer.
It was hardly surprising. Trudeau had scant regard for the old Liberal Party and had once dismissed the sainted Pearson as the unfrocked prince of peace for allowing American nuclear missiles to be stationed in Canada.
One of the arresting changes in that leap of generations would be the role of French.
In 1968, with the exception of Trudeau and Paul Martin Sr., attempts at French by candidates for the Liberal leadership were an embarrassment, not least because nobody really seemed to care how badly he spoke.
That indifference did not last long. Among most of the candidates for the Liberal leadership in 2013, French was far from perfect but it was not embarrassing.
That change had its roots in the early years of the Trudeau government. Almost by stealth the capacity to speak French became a step up the ladder of power, whether in the cabinet, the courts or the ranks of the public service.
Two western Conservatives who rose to become prime minister, Joe Clark and Stephen Harper, learned quite creditable French at a time that many fellow conservatives wanted no part of bilingualism.
An impressive number of Harper's cabinet ministers apparently can conduct the affairs of state in French as well, as can the Alberta-born chief justice of the Supreme Court and a significant number of provincial premiers, as Graham Fraser, the official languages commissioner, recently pointed out.
Fraser's explanation: "They learned French because they were ambitious, and they wanted to understand the whole country."
Whether a facility with languages provides an understanding of the country remains to be seen. Liberal Party history provides many endless examples of impressive bilingualism matched with lamentable failures of understanding.
The evidence of that could begin with Pierre Trudeau and Canada west of the Ottawa River.
A later test was the Liberal Party's attempt to replicate Pierre Trudeau's victory, the first try with Stéphane Dion, then with Michael Ignatieff, both of them impressive intellectuals but hardly miracle makers. The electoral result was close to an obliteration.
And now, 45 years later, a bit desperately perhaps, the party is trying once more to capture the magic of that dazzling Trudeau spring. These days the question is whether anyone but die-hard Liberals believe in miracles.