This article explores the political consequences of austerity politics in Spain. It argues that the economic-cum-political crisis in Spain has brought to the surface underlying structural weaknesses of its constitutional edifice accumulated over the past decades. The article sketches the parameters of the current crisis, and provides an account of the dynamic process of crisis and breakdown of Spain’s ‘constitutional regime.’ It focuses on two inter-related institutional arenas of this regime: the party system, and the territorial model of governance (the so-called $Estado\; de\; las\; Autonomías$). It analyses developments in both of these arenas, and assesses the emergent opportunities for transition to a new constitutional regime (or regimes), as well as the prospects and policy avenues open for re-equilibration. It gives an account of the transition away from two-party politics, and of the rise of new parties such as $Podemos$ and $Ciudadanos$. It pays special attention to recent events in Catalonia. It argues that the Catalan authorities’ defection from loyalty to the constitutional order was triggered in part by the dynamics of austerity, and that it has rendered the country’s constitutional edifice – but not the austerity regime – susceptible to collapse.