>War Plan Red
Completed in 1930, and declassified in 1974, Joint Board 325 – Serial 435 (NAID 16749799), from General Correspondence, 1903-1938, Record Group 225: Records of the Joint Army and Navy Boards and Committees, and abbreviated as “War Plan-Red,” called for invading Canada (CRIMSON) in the event of a war with Great Britain (RED).
During the war the state of Maine would serve as a base in order to either cut communications between Quebec and Montreal with the Maritime Provinces, or to launch land and/or air strikes against Halifax and New Brunswick. It was believed that taking over control of the Niagara power and coal from Great Britain and the western Canadian provinces would result in “an immediate strangulation of its manufacturing and munitioning capacity.”
https://text-message.blogs.archives.gov/2019/02/05/u-s-and-canada-prepare-for-war-against-each-other/
Joint Army and Navy Basic War Plan Red
https://catalog.archives.gov/id/16749799