André Lecours’ latest book has all the ingredients to become a classic of comparative politics. There is drama; there is design; and there is deduction. Emotions are provided by two of the biggest questions of our time, nationalism and secessionism. The theoretical and empirical tension between these two forms the dependent variable: Why do some regionalist-nationalist movements suddenly become secessionist? The research design to capture the answer spans four case studies where process-tracing over several decades takes place: Catalonia, Scotland, Flanders and South Tyrol. What explains the secessionist “turn” or “surge” in Catalonia and Scotland, compared to the absence of widespread independentist demand at both the popular and elite level in Flanders and South Tyrol?

The chosen research design is ingenious for two reasons. First, since only differences can explain differences, the key to solving that empirical puzzle cannot lie in European integration, nor in the fiscal and economic crisis of 2008 or other broad trends that have affected all four contexts about equally. Second, judging by the power of history, economic wealth, cultural difference and sheer numerical weight, Flemish and South Tyrolean nationalism should be more independentist, not less. After all, South Tyrol was only given to Italy as a reward after the First World War, whereas Dutch-speaking Belgians had to fight for equality despite being a majority. Yet secessionism in the form independence referendums, approved or not, has only become a serious challenge in Catalonia and Scotland. Enter Lecours’ deus ex machina: dynamic autonomy.

Dynamic autonomy is the opposite of static autonomy. Both are “ideal-types” and form “the ends of a continuum, insofar as most autonomy arrangements are not either completely resistant to change or always in movement” (40). Dynamic autonomy, in particular, is both a process and a result, both the outcome of negotiations between the central and regional governments and those negotiations itself. Dynamic autonomy is, in short, an institution understood as a broad set of more or less formalized rules of behaviour, expectations and authority that allows for modifying these very rules. In the regionalist-nationalist context, it involves recognition of collective diversity, respect for different points of view, and deliberation on top of the standard giving and taking to do with more basic interests such as infrastructure, taxation, or alternative economic models. Hence: “Static autonomy strengthens secessionism while dynamic autonomy weakens it” (194).

The book is structured around this key insight. Chapters 1 and 2 detail what we know so far and promise what a focus on dynamic autonomy will reveal. Chapters 3 and 4 highlight how its absence from Catalonia and Scotland has contributed to nationalism increasingly morphing into secessionism. Chapters 5 and 6 dissect the nature and function of dynamic autonomy in Flanders and South Tyrol: ever-growing decentralization through state reforms in Belgium; widening of autonomy already granted through a bilateral commission in Italy. Chapters 7 and 8 apply the insights thus gained to three other cases—the Basque Country, Puerto Rico and Quebec—and further refine the position of dynamic autonomy in secessionist theory.

For all its analytical worth, however, dynamic autonomy remains a surprisingly fuzzy concept. We are told, early on, that “the nature of autonomy is more important than its degree or design” (9). But, surely, powers over language and education matter more to nationalist groups than competences in agriculture and criminal law; and without sufficient own-source funding and/or unconditional guaranteed transfers, nothing much can be undertaken to begin with. More importantly, dynamic autonomy appears in so many forms that it becomes hard to see where it ends: from “formal constitutional reforms” in Belgium (179) to technical interpretation in the shadow of parliamentary scrutiny for South Tyrol (180); from newly bargained intergovernmental agreements transformed into positive law in Quebec (167) to the mere perception of being able to change a region's status and personal exit options in Puerto Rico (157). If dynamic autonomy is all that, what is it?

The second point screaming for further research is the interaction of dynamic autonomy with other institutions, such as the party system and forms of democracy. Could, for instance, the real hero of the Belgian success story—at least insofar as secessionism has been discouraged—be consociational democracy overall and proportionality in Flanders, forcing parties within and across levels to negotiate and thus encouraging a similar mindset as that allegedly caused by dynamic autonomy alone? Or is the devil even more in the details, since both the Belgian and the South Tyrolean political systems constitutionalize the much-needed parity of esteem, whereas the Spanish and British systems of vertical negotiation are much more reliant on the electoral ebbs and flows at both levels?