I posted this here because it probably requires a POD before 1900. How can we make European colonial empires last as long as possible? It seems there's a certain shelf life to just having police states, as Portugal basically tried to do everything it could and they still couldn't hang on longer than the 1970s. I'm guessing we need to change something other than military force. Preventing nationalism? A more isolationist or actively imperialist US that didn't encourage anti-imperialism?