The invasion of Ukraine by Russia and the attempts at territorial annexation that go with it, confirm — as the annexation of Crimea by Moscow had done in 2014 — the resurgence of an aggressive nationalism in Europe, contesting borders established over the course of History. This situation puts Europe in a particularly complicated position, since, though European construction and the progressive expansion of the EU have enabled relative geopolitical stability to be maintained on the Old Continent, some latent territorial disputes persist and could find a way to re-emerge in the current context. The way the international community — and the EU, in particular — reacts may turn out to be crucial in the way some claims disputing established frontiers play out. In his European Chronicle, Jean-François Drevet provides a conspectus of the dangers inherent in the ‘poison of border revisionism’. He stresses the degree to which some of the EU’s compromise arrangements (for example, in Cyprus, the Balkans or the Caucasus), which are not always consonant with the democratic values it advocates, might end up posing problems and requiring clarification, since the progress — or otherwise — of revisionist sentiments could well depend on the attitude adopted by the EU towards these sensitive and, as we have seen, potentially explosive issues.