This article studies the interactive effect between intra-party heterogeneity and individual attitudes on vote choice for the case of populism. We draw on party manifestos to measure populism of 26 cantonal branches of the SVP, relying on a quantitative text analysis. These estimates are related to individual-level Selects data from the 2015 National Council elections on voter attitudes regarding populism and voting decisions. Controlling for alternative explanations, we test whether populist attitudes interact with a higher degree of populism in the cantonal branch of the SVP in the explanation of the vote for the party. We show that there is a variety of populism (or general heterogeneity) between the different cantonal branches of the SVP. On the individual-level, populist attitudes appear to smoothly translate into a SVP vote, and there is supporting evidence regarding the interaction between individual and contextual populism.
