Those wedded to the supremacy of ethnic nationalism often allege that it is natural. But there are lots of ethnic or ethno-religious groups in the world that are not nation-states. Sikhs, Jains, Afro-Brazilians practicing Condomble, Berbers, the Quechua, Mayans, etc., etc., etc. There are lots of multi-ethnic states. In a modern world of globalization, significant population movements are common (think of all the Italians who went to the US and Argentina). Maintaining a monochrome ethnic nationalism is more and more difficult and therefore requires more and more violence, regimentation and legal legerdemain. Me, I doubt if it is viable in the medium to long term.