The plan "includes special notice ... about the Royal Canadian Mounted Police and how they were not a force to be taken lightly in a military action."
Pardon my arrogance, but I think the US military can handle a few guys on horses. Dragoons were formidable in, say, the eighteenth century. But since the advent of what are called in military parlance "big guns," soldiers are much less afraid of dandies prancing around on horses.
That is not to say that the Canadians do not pose a threat. They too have a plan.
"The department in Canada responsible for war planning had an annual budget of just $1,200. During the clandestine information-gathering for Defense Scheme Number One, staff members of the department actually entered the United States to take photographs and to procure free maps at gas stations."
Oh - my - God! They've been procuring our free maps! Will they stop at nothing?