I am curious if there are any historical examples whereby the territorial and/or demographic majority of a country seceded from a minority as perhaps they realize maintaining it is more trouble than it's worth and yields a more optimal net result than controlling it by force.
For a hypothetical example, if China decided to, rather than forcefully assimilate Uighurs into Chinese society, it would be easier for the rest of China to secede from Uighuristan regardless of what the Uighurs thought about it (maybe they like being a part, for some reason, and don't want independence). Or if Northern Macedonia decided to force ethnic Albanians from the west of the country to secede as they would rather have a more culturally homogeneous country.
I'd like to know whether there are any historical instances of such policy.