Defence Scheme No. 1 was a war plan created by Canadian Director of Military Operations and Intelligence Lieutenant Colonel James “Buster” Sutherland Brown, for a Canadian pre-emptive attack against the United States in the (hypothetical) case of a conflict between the United States and the British Empire.
The USA has had dreams of this forever.
https://en.m.wikipedia.org/wiki/War_Plan_Red
Not to fear, we also made similar plans. (Should have done it when we had the chance)
https://en.m.wikipedia.org/wiki/Defence_Scheme_No._1