The North Atlantic triangle is a theoretical construct for studying the history of Canadian foreign policy. It seeks to explain the importance of British—American relations to Canada's security, and even survival, during the late nineteenth and early twentieth centuries.

The triangle in question was Canada, the United States of America, and the United Kingdom. This triangle was invisible to Americans or Britons, for whom Canada was a side issue at best, but it was vital to Canada. Canada was intimately involved with both countries, and needed good relations between them to its own security. The primary concern of Canadian governments was to avoid a repetition of American invasions of 1775

Invasion of Canada (1775)

The Invasion of Canada in 1775 was the first major military initiative by the newly formed Continental Army during the American Revolutionary War. The objective of the campaign was to gain military control of the British Province of Quebec, and convince the French-speaking Canadiens to join the...

 and 1812-1815

War of 1812

The War of 1812 was a military conflict fought between the forces of the United States of America and those of the British Empire. The Americans declared war in 1812 for several reasons, including trade restrictions because of Britain's ongoing war with France, impressment of American merchant...

, when Canada had been used as the battlefield where American and British differences were settled.

Culturally and philosophically, most Canadians of the era (especially the ethnically British majority) identified with Britain and the British Empire and distrusted the United States, but at the same time many Canadians were eager to trade with the large, growing, and nearby market in the United States.

Overview

Canada's interest in Anglo-American relations began as early as the Canadian-American Reciprocity Treaty

Canadian-American Reciprocity Treaty

The Canadian American Reciprocity Treaty, also known as the Elgin-Marcy Treaty, was a trade treaty between the colonies of British North America and the United States. It covered raw materials and was in effect from 1854 to 1865...

 of 1854, when Canada was still a disunited collection of British colonies. The short era of increased trade with the US that the treaty created (lasting to 1866) deeply influenced Canadian trade policy and attitudes towards the US for years to come, encouraging the free traders. But the treaty's cancellation by the Americans also raised suspicions in Canada.

Of even more serious concern were the repeated war scares between Britain and the northern, Union government in the American Civil War, which threatened Canada with another invasion over the Trent Affair

Trent affair

The Trent Affair, also known as the Mason and Slidell Affair, was an international diplomatic incident that occurred during the American Civil War...

, the Alabama Incident, and so on.

After Canada federated and became a self-governing dominion

Canadian Confederation

Canadian Confederation was the process by which the federal Dominion of Canada was formed on July 1, 1867. On that day, three British colonies were formed into four Canadian provinces...

 in 1867, Canada's new federal government became part of Anglo-American relations. At the Washington conference of 1871 which discussed all issues of Anglo-American relations, Canada's prime minister, John A. Macdonald

John A. Macdonald

Sir John Alexander Macdonald, GCB, KCMG, PC, PC , QC was the first Prime Minister of Canada. The dominant figure of Canadian Confederation, his political career spanned almost half a century...

 took part as part of the British delegation. This was the beginning of a kind of triangle diplomacy lasted in various forms for decades.

Canadian Prime Minister Borden

Robert Borden

Sir Robert Laird Borden, PC, GCMG, KC was a Canadian lawyer and politician. He served as the eighth Prime Minister of Canada from October 10, 1911 to July 10, 1920, and was the third Nova Scotian to hold this office...

 sought to create an Anglo-American alliance during the Paris peace talks of 1919, and pushed Britain to renounce its alliance with Japan

Anglo-Japanese Alliance

The first was signed in London at what is now the Lansdowne Club, on January 30, 1902, by Lord Lansdowne and Hayashi Tadasu . A diplomatic milestone for its ending of Britain's splendid isolation, the alliance was renewed and extended in scope twice, in 1905 and 1911, before its demise in 1921...

 and instead come to an agreement with the US during the 1920s. Canada also hoped to become part of the inner circle of allied decision making during the Second World War, and Prime Minister Mackenzie King hosted Winston Churchill

Winston Churchill

Sir Winston Leonard Spencer-Churchill, was a predominantly Conservative British politician and statesman known for his leadership of the United Kingdom during the Second World War. He is widely regarded as one of the greatest wartime leaders of the century and served as Prime Minister twice...

 and Franklin Roosevelt in Quebec City

Quebec Conference, 1943

The First Quebec Conference was a highly secret military conference held during World War II between the British, Canadian and United States governments. The conference was held in Quebec City, August 17, 1943 – August 24, 1943. It took place at the Citadelle and at the Château Frontenac. The...

for that reason.