After 1945 what happened was rather the opposite: with one major exception boundaries stayed broadly intact and people were moved instead.
Tony JudtUndergraduates today can select from a swathe of identity studies.... The shortcoming of all these para-academic programs is not that they concentrate on a given ethnic or geographical minority; it is that they encourage members of that minority to study themselves - thereby simultaneously negating the goals of a liberal education and reinforcing the sectarian and ghetto mentalities they purport to undermine.
Tony Judt