The alienation of mainstream parties from their voter base is an important potential driver of the remarkable electoral success of anti-system political parties in Western democracies, but has received relatively little attention compared to the role of economic grievances and cultural anxieties. This paper empirically tests conjectures derived from theories of party cartelization through an examination of the long-term impacts of the French government’s effective ignorance of French voters’ rejection of the EU constitution in a popular referendum held in May 2005. Leveraging a dataset of European Parliament election results for more than 36,000 metropolitan French municipalities (“communes”), we employ panel data analyses to examine the electoral impact of the bypassing of the referendum result. We find strong and consistent evidence that in municipalities that had rejected the referendum, electoral turnout decreased, and centrist parties lost electoral support at the expense of anti-system parties. The larger the communal No-vote shares, the larger are the effects we observe. The patterns are clearer on the political Left than Right, and gradually wane out over time. Complementary analyses of survey data indicate that the mechanisms behind these outcomes center on increased distrust and dissatisfaction with the national government, rather than with the EU. The paper contributes to the literature on the political economy of the party politics of EU (dis)integration by analyzing the electoral consequences of a controversial decision by governing elites in one of its largest member states to bypass a popular vote against further integration.