How mainstream parties' responses to populist challengers affect citizens

When populist challenger parties enter parliament for the first time, mainstream parties’ initial reaction has often been to portray them as undemocratic political pariahs. Yet, in many instances, mainstream parties have switched strategy and no longer demonize and ostracize their populist challengers. I call such strategies delegitimizing and legitimizing strategies, respectively. In this study, I examine citizens’ reactions to (changes in) such strategies by mainstream parties. More specifically, I investigate three different reactions by citizens to mainstream parties’ (de-)legitimizing strategies: a) citizens’ evaluations of the targeted challenger, b) citizens’ evaluations of the mainstream party pursuing such strategies, and c) citizens’ attitudes towards the political system. Focusing on mainstream party communication, I conceptualize and operationalize (de-)legitimizing strategies as mainstream party messages portraying populist challengers – implicitly or explicitly – as (un-)democratic. To empirically test my theoretical propositions, I implement a survey experiment in Sweden (N=2,000). The findings of this study will have important implications for our understanding of mainstream parties’ response strategies to populist challengers and their consequences for public opinion.