The Eurozone crisis and resulting economic interventions present a particular manifestation of the dilemma between globalisation and national democracy, one in which supranational involvement led to an unprecedented reduction in democratic governance. This has been linked to an erosion in support for the domestic political system, but the precise mechanism is still debated. This article tests two mechanisms proposed in the recent literature: firstly, that citizens perceived that their domestic system’s autonomy was constrained by the economic interventions, which led citizens to reduce their support for the domestic system; secondly, that the decline was due to worsening economic evaluations. This article tests these arguments together at the individual level for the first time using a multilevel analysis of European Election Study data, and replicates the results with a case study of Portugal. The analysis finds no support for the autonomy argument, but instead points to the crucial role of economic evaluations.