War Plan Red was a military document outlining a hypothetical war between the United States and the British Empire (the "Red" forces). It was developed by the United States Army during the mid 1920s, and was officially withdrawn in 1939, when it and others like it were replaced by the five "Rainbow" plans created to deal with the Axis threat.

The war was intended to be a continental war, waged primarily on North American territory between the United States and the British Empire. The assumption was that Canada would represent the ideal geographic forum through which the British could wage war against the United States.

Defence Scheme No. 1 was a plan created by Canadian Director of Military Operations and Intelligence Col. James "Buster" Sutherland Brown, for a Canadian counter-invasion of the United States.