Nationalism in it's best incarnations has allowed in Europe to develop distinct societies, with their excelling qualities, distinct cuisines, Scientific establishments, cultures. fiercely defending their territories and integrities. That competition, while often messy, has produced much of the advancement the human race has seen, Hats off to the greater other civilisations, ethnicity based, too! and all projecting these attributes into the immigration areas of the world.
Shame that these outstanding developments are now on the endangered species list.
Nationalism has solved the problem of identity theft, the race to the bottom.