Borders do not acknowledge and register an already existing estrangement

As Frederick Barth explained, borders do not acknowledge and register the already existing estrangement; they are drawn, as a rule, before the estrangement is brought about. First there is a conflict, a desperate attempt to set 'us' apart from 'them'; then the traits keenly spied out among 'them' are taken to be the proof and the source of a strangehood that bears no conciliation. Human beings being as they are multi-faceted creatures having many attributes, it is not difficult to find such traits once the search has started in earnest.

Zygmunt Bauman, Liquid Modernity (Polity Press, 2012) p. 177