American lives were felt to be in such danger after the 1979 seizure of the U.S. embassy in Iran that Ottawa judged it inconceivable not to offer every assistance possible, including authorizing Canadian diplomats in Tehran to collect military intelligence for Washington.
One of Canada's foremost experts on international relations said the ambassador, Ken Taylor, took considerable risks in running an espionage operation that was helping the United States to plan a commando raid on Iran - risks that included allowing a U.S. Central Intelligence Agency operative to work from the Canadian embassy.
"But the physical threat to those people was so real," said Janice Stein, director of University of Toronto's Munk Centre for International Studies.
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Student militants overran the U.S. embassy at the height of the Iranian revolution, taking 63 Americans hostage. Six personnel and their spouses escaped capture and were given shelter in the residences of Mr. Taylor and the Canadian embassy's immigration counsellor, John Sheardown.
"Maybe a distinction wasn't clearly being drawn between getting Americans out of the embassy and getting them out of our residences," said Allan Gotlieb, at the time Canada's undersecretary of state for external affairs (deputy foreign minister). "I don't know if you could make an easy distinction.
"It was one of our finest hours. We didn't cower. We basically knew where the Canadian people were. We all had the same moral compass."
Mr. Taylor and his embassy staff, assisted by the CIA, successfully got the six Americans hidden by the Canadians out of Iran. The subsequent commando raid planned to free the hostages, Operation Eagle Claw, was a disastrous failure and they were held for 444 days before being released.
Mr. Gotlieb drew parallels between Mr. Taylor's activities 30 years ago - a detailed account of which appears in a new book released on the weekend, Our Man in Tehran , by Trent University historian Robert Wright - and how governments today share intelligence on terrorist threats to airplanes.
"Without sharing, there'd be a hugely increased risk of terrorist destruction," Mr. Gotlieb said.
In his book, Prof. Wright describes Mr. Taylor as the "de facto CIA station chief in Tehran," a label former government officials involved with the file find jarring. His espionage group comprised himself, a Canadian Forces sergeant and a CIA operative code-named "Bob" who Mr. Taylor said became part of the Canadian embassy "community."
Ms. Stein said it wouldn't have been unusual for Canadian diplomats to be collecting intelligence on behalf of the Americans.
"What is less usual is that a CIA agent would have worked out of the Canadian embassy. Had he been discovered, he would have put the whole embassy staff at risk."
Then-prime-minister Joe Clark said in an interview Sunday that he was not aware of the Canadian embassy presence of "Bob," but "it is not an accurate characterization to suggest that Ken Taylor was taking instructions from, or in that sense working for, the U.S. It was a Canadian initiative."
He said that once the U.S. embassy hostages had been taken and the Americans no longer had the "capacity on the ground" to get information out of the country, "we naturally stepped up our co-operation."
He said there was a U.S. request that the Canadians provide information helpful to planning Eagle Claw, but he contradicted the assertion in Prof. Wright's book that U.S. President Jimmy Carter made it directly to him.
The request, he said, would have been made at a lower level and would not have required his authorization.
"It would have been to step up an activity that was already in place, and the government - I and Flora [Flora MacDonald, Mr. Clark's foreign affairs minister]- had both indicated we wanted to be helpful on getting the diplomats out."
But Prof. Wright said yesterday he is confident that the request was made at the highest level.