Canada and the United States have been economic and military allies for most of the 20th century, notwithstanding the bad chemistry between our leaders from time to time. Prime Minister Stephen Harper has done a reasonable job of repairing the damage in relations caused by the Paul Martin Liberals. However, throughout much of American history, many influential politicians were firmly committed to the expansionist ideology of Manifest Destiny. This is the belief that the United States has an “inherent, natural and inevitable right” to annex all of North America.
So it should not be a huge surprise to learn that the United States military had prepared a Joint Army and Navy Basic War Plan to invade Canada in the late 1920s, and updated it in 1935. The document called War Plan Red was declassified in 1974. However, the story resurfaced in a Washington Post (Dec.30, 2005) article by journalist Peter Carlson headlined Raiding the Icebox; Behind Its Warm Front, the United States Made Cold Calculations to Subdue Canada.