The strongest legacy of nationalism in contemporary political thought is the idea that the nation-state is something ‘natural’, the obvious, default way of organizing and dividing societies into states. The idea of the self-determination of peoples appears as a natural right, and the social solidarity and ease of communication that obtains within cultural communities appears as a logical basis for state cohesion and viability. Certainly, wherever cultural fault lines hamper communication or solidarity within the state, its viability might be threatened as a result.

But there are reasons to query, all the same, this acceptance of the nation-state as the inevitable and natural constitutional default. While a cultural community would indeed appear as an almost-necessary condition for state cohesion, it is not a sufficient condition: a communal language does not by itself create a language community. Holland and Flanders, or Ireland and Britain, will not, and would not, easily coalesce into a single nation-state despite their communal languages.

Also, defining the state on the basis of its ethnocultural constituency will not by itself guarantee healthy relations within the state. Many, indeed the great majority, of the European nation-states that emerged out of the ruins of multi-ethnic empires in 1919, slid towards monocultural intolerance and autocratic or despotic regimes: the interwar years saw authoritarian, non-democratic state structures develop in Poland under Piłsudski, in Romania under Tătărescu and his successors, in Greece under Metaxas, in Hungary under Horthy, and in Austria under Dollfuß. Serbia under Milošević offered a post-1989 analogue, which must raise concerns over recent trends in countries where ethnopopulist parties are now in government. A belief in the state’s nationality does not guarantee a commitment to democracy (if we understand democracy to imply the constitutional acceptance of human rights, and of international treaties, overseen by an independent judiciary).

A century after the Paris Peace Treaties, which enshrined the nationality principle in the European state system, it is timely to reflect, once again, on the relations between nation and state. What is, fundamentally, a state?

A state is, commonsensically, a fiscal-administrative organization claiming sovereignty and a monopoly on legitimate violence.