[dragonwriter]

> These plans were made not because we really had any intention of invading Canada or Mexico

To be fair, Americans and/or pro-US Texans and/or pro-US “filibusters” fought wars in and opposite one or another Mexican regime (sometimes alongside a competing Mexican regime, as in a war between the Mexican Republic and the Empire of Mexico) in the 1810s, 1820s, 1830s, 1840s, 1850s, 1860s, 1900s, and 1910s.

So, having military contingency plans for invading Mexico in the 1930s wasn't unreasonable, and not just as some kind of abstract exercise.

[openasocket]

That's true, a US-Mexican war in that era wasn't nearly as far-fetched as an invasion of Canada. A better example would have been War Plan Gold, which involved war with France

[saalweachter]

While it had been over a century since our last attempt to invade Canada by then, there has always been a certain flavor of American in love with the idea of continuing the doctrine of Manifest Destiny until the entire continent has been conquered.

(Those snooty Australians lording their continent over us, we'll show them.)