Joint Army and Navy Basic War Plan Red was a war plan created by the United States Army and Navy in the late 1920s and early 1930s to estimate the requirements for a hypothetical war with Great Britain (the "Red" forces).
War Plan Red first set out a description of Canada's geography, military resources, and transportation, and went on to evaluate a series of possible pre-emptive American campaigns to invade Canada in several areas and occupy key ports and railways before British troops could provide reinforcement to the Canadians - the assumption being that Britain would use Canada as a staging point. The idea was that the American attacks on Canada would prevent Britain from using Canadian resources, ports, or airbases.[2]
A key move was a joint US army-navy attack to capture the port city of Halifax, cutting off the Canadians from their British allies. Their next objective was to "seize Canadian Power Plants near Niagara Falls"[5] This was to be followed by a full-scale invasion on three fronts: From Vermont to take Montreal and Quebec, from North Dakota to take over the railhead at Winnipeg, and from the Midwest to capture the strategic nickel mines of Ontario. In parallel, the U.S. Navy was to seize the Great Lakes and blockade Canada’s Atlantic and Pacific ports.[2]