So, obviously, the UK voted out. Just in case you hadn't heard. I keep thinking about what Richard Dawkins said in his recent AMA. To paraphrase because I can't find the post now, he basically said "I'm Remain, but I think it's disgusting that ignoramuses like me can decide, who are neither economists nor historians". And then I remembered that I have access to a futuristic communication network that will let me ask some historians.
Just to be clear, I'm not asking about anyone's opinion on the Brexit. Pretty sure that is forbidden and it's your own business anyway. I just want to know if there are any historical precedents for a core member of a federation (or quasi-federation, hegemony, trade alliance, whatever) leaving by choice (as opposed to violence/disaster) and what the fallout was, or if we are in truly uncharted waters.
You could look at Yeltsin's de facto secession of Russia from the USSR; the Chinese Revolution of 1911, which started with several different provinces seceding individually from Qing empire; Singapore being expelled from Malaysia in 1965 (though that wasn't a secession); the referendum in the 1920s by which Burgenland became a state of the Republic of Austria although it had previously been under Hungarian jurisdiction (and the attempt at the same time by Vorarlberg to secede from Austria and join Switzerland); threats of secession from the USA by some factions in New England at the Hartford Convention following the war of 1812; and Henry VIII's removal of the Church of England from Rome's ecclesiastical jurisdiction.