Canadian declaration of war

A declaration of war by Canada is a formal declaration issued by the Government of Canada (the federal Crown-in-Council) indicating that a state of war exists between Canada and another nation. It is an exercise of the Royal Prerogative on the constitutional advice of the ministers of the Crown in Cabinet and does not require the direct approval of the Parliament of Canada, though such can be sought by the government. Since gaining the authority to declare war under the Statute of Westminster 1931, Canada has declared war only during the Second World War.

After Germany invaded Poland on September 1, 1939, the United Kingdom and France declared war on September 3. To assert Canada's independence from the UK, as already established by the Statute of Westminster 1931, Canada's political leaders unnecessarily decided to seek the approval of the federal parliament to declare war. Parliament was not scheduled to return until October 2, but returned to session early on September 7 to consider the declaration of war.

On September 9, the House of Commons and Senate approved authorization for a declaration of war. The Cabinet then drafted an Order in Council to that effect. On September 10, Vincent Massey, Canada's High Commissioner to the United Kingdom, brought the document to King George VI, at the Royal Lodge, Windsor Great Park, for his signature, whereupon Canada had officially declared war on Germany. In his capacity as the government's official recorder for the war effort, Leonard Brockington noted: "King George VI of England did not ask us to declare war for him—we asked King George VI of Canada to declare war for us."

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