In December 2016, Italian voters were called to the polls to express their approval for the Consitutional reform elaborated by the government led by Matteo Renzi. The campaign, however, only marginally dealt with the actual content of the reform, as both supporting and opposing parties heavily framed it as a referendum on the government and its leader. Prime Minister Renzi himself navigated through the first months of the campaign under the promise (eventually fulfilled) that he would have resigned had the reform been rejected by Italian voters. Against this background, the aim of our paper is that of investigating the individual-level determinants of voting behaviour in the 2016 Constitutional referendum. Our framework builds on the literature on opinion formation in direct democracy (Kriesi, 2005). Firstly, we hypothesize that Italian citizens’ voting behavior is better explained by their reliance on the "heuristic path" to opinion formation (individual attitudes towards the government and its prime minister) as compared to the "systematic path" (voters' evaluation of the actual contents of the Constitutional reform). Secondly, we extend the “personalization of politics” theory to the field of direct democracy, and hypothesize that – among the aforementioned decisional heuristics – voters’ approval of the prime minister is the best predictor of their vote choice in the referendum. Data comes from a post-electoral survey conducted by the Italian National Election Study (ITANES) on a representative sample of Italian voters in the aftermath of the referendum.
