Methodological nationalism

In social science, methodological nationalism is an intellectual orientation and pattern in scholarly research that conceives of the nation-state as the sole unit of analysis or as a container for social processes. This concept has largely been developed by Andreas Wimmer and Nina Glick Schiller, who specifically define it as "the assumption that the nation/state/society is the natural social and political form of the modern world".

Source: Wikipedia — Methodological nationalism (CC BY-SA 4.0)