The invasion of Canada by the United States of America seems like something that belongs in only the most dystopian of fiction, but it's the exact scenario laid out in War Plan Red, an actual attack strategy drawn up by the US government during the interwar period between WWI and WWII.
What if the US carried out War Plan Red? In short, it would spell bad things for America's neighbors to the north. The comprehensive strategy - designed as part of an overall war against the United Kingdom - called for a full-on invasion and occupation of Canada to prevent the British from using it as a base of attack. Furthermore, this occupation was intended to be permanent, essentially turning Canada into the 51st state and further achieving the concept of Manifest Destiny.
The US Created War Plans For Potential Enemies Around The World, Including Several Key Allies
The period between World Wars I and II is mostly known as a time of peace, but that doesn't mean the planet's superpowers weren't preparing for conflict. The United States of America emerged from WWI as a major victor in terms of combat, economy, and influence, and firmly established its militaristic fortitude. The US looked like a country that could take on anyone, and that's exactly what the US government prepared for as the '20s turned into the '30s.
Toward the end of the '20s, they began drawing up a series of color-coded war plans for the nations the US might face off against in potential conflicts. The list was broad and included a number of key allies.
War Plan Red Was The Strategy For A War Against Britain
The war plan the United States government and military invested the most interest in was War Plan Red - the official strategy guide for a battle against their former colonial masters in the United Kingdom. The British Empire might not have been what it was before World War I, but the Commonwealth still had a global reach that would play a role in any conflict.
The Plans Were Created At The Highest Levels Of Government
War Plans Red and Crimson - and other stratagems, including Black for Germany, Orange for Japan, and Green for Mexico - weren't just something dreamed up by bellicose generals as a side project. All the color-coded war plans were created by the US Joint Planning Committee - the precursor to the Joint Chiefs of Staff - and they involved plenty of input from the Army and Navy at every step of the way.
These decisions occurred at the highest levels of government, as the Secretary of War and the Secretary of Navy needed to approve the plans - which they did in May 1930.
Canada Was The Only Real Target In War Plan Red
War Plan Crimson was the real meat of War Plan Red, which didn't bode well for America's neighbors to the north. In the event of a conflict with Britain, the United States didn't plan on doing much fighting outside of North America. Instead, the US prioritized an invasion of Canada under the logic that preventing Britain from using their former colony as a base of operations would keep the American homeland safe.
Beyond that, the Americans believed they could win a war of attrition with the United Kingdom and saw the occupation of Canada as the key to victory.