The shock of the Russian invasion of Ukraine is that it demonstrated a form of aggression most people thought belonged to an earlier time.

Following the Napoleonic era, a war of conquest against a recognised sovereign state was considered legitimate only if fought in the name of national self-determination.

National self-determination remained a worthy goal in the Wilsonian world of 1918, but its practicalities were always uncertain in the mix of languages and what were deemed to be ‘races’ that still characterised Europe.