Canada played a minor, but occasionally important, role in the Cold War. Throughout the struggle Canada was firmly on the side of the United States and the West.

Early Cold War

There was never any doubt as to which side Canada would join in the Cold War. The cultural, economic, and historical ties with the United States and the United Kingdom were extremely strong.

Canada was a founding member of the North Atlantic Treaty Organization. Canada was, in fact, one of its most ardent supporters and pushed (largely unsuccessfully) to have it become an economic and cultural organization in addition to a military alliance.

Fears of communist espionage

One of the most important early events of the Cold War occurred in Canada when Igor Gouzenko, a cipher clerk working at the Soviet embassy in Ottawa, defected. His revelations of widespread Soviet espionage against the west shocked both the public and world governments.

Canada began a widespread, but mostly hidden, programme of removing security threats from government and the military. This included removing suspected communist sympathizers and homosexuals. The RCMP even developed the "Fruit Machine" to test if a man was gay. Unlike in the United States with McCarthyism the cleansing was mostly done in private. Those fired would not even be told why that had been let go, and were told a variety of lies. The government helped those who were fired find new jobs and many were relocated to academia.

The United States wished the Canadian government would go further asking for a purging of trade unions, but Canada saw this as American hysteria. The American officials were especially concerned about the sailors on Great Lakes freight vessels, but Canada again refused to act. The Canadian communist party was never outlawed, unlike in the States. In fact, Canada now is the only Western country with two official communist parties.

Canada-U.S. Tensions

To defend North America against a possible enemy attack Canada and the United States began to work very closely together in the 1950s. NORAD created a joint air-defence system. In northern Canada the Distant Early Warning Line (Dew Line) was established to give warning of Soviet bombers heading over the pole. Great debate broke out while John Diefenbaker was Prime Minister as to whether Canada should accept U.S. nuclear weapons on its territory. Diefenbaker had already agreed to buy the BOMARC missile system from the Americans, which would be useless without nuclear warheads, but balked at permitting the weapons into Canada.

In the 1963 Canadian election Diefenbaker was replaced by the famed diplomat Lester B. Pearson, who accepted the warheads. Further tensions developed when Pearson criticized the American role in the Vietnam War in a speech he gave at Temple University in Philadelphia, Pennsylvania. See also Canada and the Vietnam War.

Canada also refused to join the Organization of American States, disliking the support and tolerance of the Cold War OAS for dictators. Under Pearson’s successor Pierre Trudeau US-Canadian policies grew further apart. Trudeau removed nuclear weapons from Canadian soil, formally recognized the People's Republic of China, and decreased the number of Canadian troops stationed at NATO bases in Europe.

End of the Cold War

Brian Mulroney and Ronald Reagan had a far closer relationship, but the 1980s also saw widespread protests against American testing of cruise missiles in Canada's north.

When the Cold War ended, Canada, like the rest of the west, was delighted. All the remaining Canadian troops were withdrawn from Europe, military spending was cut, and the air raid sirens were removed in Ottawa. The Diefenbunker, Canada's elite fallout shelter, was turned into a tourist attraction. Canada continues to participate in Cold War institutions such as NORAD and NATO, but they have been given new missions and priorities.