Stephen Clarkson walked into the classroom at the University of Toronto where 50 undergraduates were waiting for him to begin a course on the intricacies of political economy.
With a glint in his eye, Prof. Clarkson turned his back to them and scrawled "S&M" in a large hand across the chalkboard. Then, suppressing a smile, he said, "Students, this class is about S and M" – pregnant pause – "states and markets."
It was, perhaps, a bit of a risqué opening for a man who was generally so refined – an elegant intellectual and one of the country's foremost liberal-left thinkers. But his students were hooked.
Prof. Clarkson was many things: An extraordinary political researcher, a prolific and multiple-award-winning author of books about trade and politics, a young radical, a fervent nationalist, a former Toronto mayoral candidate, a devoted father, and, over the course of his lifetime, the husband of three intensely bright and accomplished women.
But he was, above all, a magnificent teacher who fostered a passion for learning, the ability to think critically, and the desire to know more about the world at large in the minds of the young people who populated his lectures.
"Teacher, scholar and political scientist – Canada has lost a great mind in Stephen Clarkson," wrote Prime Minister Justin Trudeau on the social media site Twitter after learning of Prof. Clarkson's death on Feb. 28 in Freiburg, Germany, at the age of 78.
He succumbed to pneumonia, which took advantage of an immune system compromised by several years of chemotherapy to combat multiple myeloma. While his death was a shock, it was at least somewhat fitting that he fell ill while on a research trip in Portugal with a group of students.
"He was very committed to his students and wanted to continue teaching until the end. And he did exactly what he intended to do," says his friend Louis Pauly, the chair of the University of Toronto's political science department.
His brother Austin Clarkson says Prof. Clarkson's death was "devastating," and the hurt was compounded by the fact that it cut short his dream of holding a conference next year where international experts would collaboratively begin to set rules governing the operations of transnational corporations that affect the rights of sovereign countries. It was a goal that was aided by his fluency in French, German and Spanish.
"He really was a visionary," said Austin Clarkson. "He had a tremendous number of wheels in motion and it's tragic because he was pushing toward a culmination of many years of work."
Prof. Clarkson spent his life studying and writing about the need to protect and nurture the Canadian economy and identity, though he was British, born in London, England, on Oct. 21, 1937, just before the start of the Second World War.
His father, George Clarkson, was a Torontonian who had travelled to Leeds to obtain a master's degree in chemistry. There, he met Alice Mannaberg, a gifted pianist and social activist whose Jewish ancestors had converted to Christianity.
The two married and had seven children, of whom Stephen was the youngest. When the senior Mr. Clarkson observed the treatment of Jews after Austria was annexed by Germany, he moved his large family back to Canada.
The Clarksons purchased a farm north of Toronto, which George Clarkson operated at the same time he ran a printing business in Buffalo, N.Y.
Like the other younger Clarkson children, "Stephen really enjoyed a free-range childhood," said Austin Clarkson. Summers were spent haying, weeding, picking fruit and tending to the cattle, pigs and chicken. Winters meant commuting the long distance each day to Upper Canada College in midtown Toronto, where he came to loathe the "Englishness" of the school.
Austin Clarkson remembers a precocious brother who, although five years younger, refused to be left behind.
"By the age of 10, he was a very keen bridge and canasta player and could hold his own in our marathon family tournaments of Monopoly," he said. "He was a fierce and dogged competitor, but he was generous in victory and in defeat."
After graduating from high school he was accepted into the University of Toronto's Trinity College, where he studied history and modern languages. It was there that he met fellow student Adrienne Poy, who would become his first wife and eventually, in 1999, governor-general of Canada.
"It was a time of debating what life is about, and where the country was going," says Tim Reid, who attended the school in the same years and later became a member of the Ontario legislature. "We were both, in those days, left-wing Liberals. We were going to change the world."
Mr. Reid said his friend was "a very kind person with a very tough intellect."
Stephen Clarkson accepted a Rhodes scholarship and went to Oxford to obtain a master's degree in philosophy, politics and economics. Then he moved to Paris to earn his doctorate at the Sorbonne.
"We were both radicals," recalled Mr. Reid, who was also a Rhodes scholar and joined his friend at Oxford. "There was a kind of activism that was just starting. We were really worried about South Africa and apartheid and all of those kinds of things."
Back in Toronto, Prof. Clarkson was appointed to the political science department at the University of Toronto in 1964. Adrienne Clarkson was starting her career as a broadcaster with the CBC and the couple were considered to be among the city's glamorous young social elite. They had two daughters, Kyra and Blaise.
In the late 1960s, Prof. Clarkson was enthralled by the rise of former prime minister Pierre Elliott Trudeau and campaigned for the Liberal nomination in the Toronto riding of Davenport, which he did not win.
But he and others who shared the same political affiliation decided that the operation of Toronto city hall would be improved by the introduction of parties to municipal politics. At a tumultuous meeting, where his nomination was seconded by Mr. Reid, he was named the Liberal candidate for mayor.
Writing in The Globe and Mail in 1969 during that campaign, Michael Enright, who is now a CBC broadcaster, said of Prof. Clarkson: "There is something so unaccountably perfect, so indefinably correct about him. ... He has the brains, the right kind of conscience, the magnificent wife, the money, the style." But Prof. Clarkson lost his mayoral bid.
Writing, editing, and teaching were clearly his strengths – and also his passions. In 1970, he published the first in a string of more than a dozen books about Canada, trade and globalization that won widespread acclaim.
He was also a leading voice for nationalism and was a significant player in the Committee for an Independent Canada, which was created by former Liberal finance minister Walter Gordon, University of Toronto economist Abe Rotstein and Peter C. Newman, who was then the editor-in-chief of the Toronto Star. Its aim was to stanch the flow of foreign capital into the Canadian economy.
"More than anything else, he was a good nationalist," says Mel Hurtig, the publisher who chaired that committee in its first year.
When Prof. Clarkson's marriage to Ms. Clarkson dissolved in acrimony in 1975, he maintained custody of their two daughters.
"Almost the day after he and Adrienne got divorced, I went out to join him in the country and he was very, very sad. He was very hurt by what was happening," Mr. Hurtig said.
But Mr. Clarkson did not stay single for long. In 1978, he married Globe and Mail journalist and author Christina McCall, the former wife of Mr. Newman. It was not just a love match; it was a meeting of the minds.
Together, Prof. Clarkson and Ms. McCall authored a two-volume biography of Pierre Elliott Trudeau called Trudeau and Our Times. The first volume, which was published in 1990, six years after Mr. Trudeau resigned, opened with the memorable line: "He haunts us still." It won the Governor-General's award for non-fiction.
Meanwhile, Prof. Clarkson was acknowledged as being one of the top teachers at the University of Toronto. The best of his undergraduates were invited to co-author papers with him, many of which were published. Every year, he took groups of students to different countries to study political economy and governance.
Joanna Langille was among the students who travelled with Prof. Clarkson to Washington. "He was fantastic," she said. "It was an absolutely amazing experience. He went way above and beyond to get to know students, to help us develop our independent critical capacity, to get out in the field, to be doing research, and to really think critically about the basic ideas that we had begun to learn about."
Jonathan Sas, another former student, said it was in Prof. Clarkson's class that he got his first taste of left-leaning Canadian nationalism and the Canadian political economy tradition. "I had always cringed at any talk of nationalism," Mr. Sas said in an online tribute to Prof. Clarkson, "but here was a professor fiercely dedicated to Canada at its best: a robust welfare state, smart and effective cultural policy, the government as agent for, and steward of, broad collective aims."
Prof. Clarkson regularly had groups of students over to his Toronto house for dinner parties, where the political banter continued long into the evening.
In contrast to the public life he lived with Adrienne Clarkson, Prof. Clarkson and Ms. McCall put a high premium on their privacy. They formed a close-knit family. She adopted his daughters and he adopted Ashley, her daughter with Mr. Newman.
"He was very devoted, absolutely" as a father, Austin Clarkson said. "He paid very close attention to all their development and was a very active and responsible dad."
When Ms. McCall died in 2005, Prof. Clarkson remembered her as "the premier political analyst of her generation."
Three years later, while studying at the Goethe Institute in Freiburg, Germany, he attended a concert and sat beside a woman named Nora Born. She turned out to be a musicologist keenly interested in the German-born composer Stefan Wolpe, whom his brother Austin had also studied. With that in common, they struck up a conversation and Prof. Clarkson was smitten.
"Stephen was relentless in his pursuit and she agreed to marry him in 2014," Austin Clarkson said.
The two travelled the world together, depending upon where his academic engagements took them.
In addition to teaching at the University of Toronto and being a prominent senior fellow of Massey College, Prof. Clarkson held positions at the Centre for International Governance Innovation in Waterloo, Ont., the Woodrow Wilson International Center for Scholars in Washington, the European University Institute in Florence and the Free University of Berlin.
The Clarksons divided their time between Toronto and Germany. He was just about to start his annual three-month residency in Berlin when he died.
Prof. Clarkson's lifelong challenge to his students, Mr. Pauly wrote, "was to resist conventional wisdom, imagine a Canada that could live up to their highest expectations, and go out into the world to experience firsthand the decision-making structures and policies that needed to be changed."
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