The following is a full-text reproduction of the 1935 plan for a US invasion of Canada prepared at the US Army War College, G-2 intelligence division, and submitted on December 18, 1935.
"Red" was apparently the military color code for Britain, where Canada was appropriately "Crimson", and the U.S. was "Blue". Also interesting, besides them naming every major city in Canada a "strategic interest"?
In 1934, War Plan Red was amended to authorize the immediate first use of poison gas against Canadians and to use strategic bombing to destroy Halifax if it could not be captured.
(via Tory Briggs)