Populists are known for their aggressive and uncompromising political style, and for rewarding a more combative behavior in their followers. Yet, virtually no evidence exists that aggressive populist rhetoric has an inciting effect among their followers towards greater support for political violence against political opponents. In this article, we present novel experimental evidence from four countries (Argentina, Czechia, Germany, Italy), assessing whether exposure to populist negative campaigning triggers greater support for political violence among their supporters. While we find only marginal evidence when looking at attacks in general, uncivil attacks from populists seem associated with a marginal uptick in support for violence among their followers – especially more severe forms of it (e.g., shooting political opponents). These results, while not excessively strong, shed a new light on the intersection between populism, aggressive rhetoric, and radical partisanship, and have possibly profound implications for a more comprehensive understanding of the roots of political violence in the public. All data and materials are openly available for replication.

How do citizens respond to political violence during election campaigns? Previous research suggests such events can increase support for the victim's party through a “rally ‘round the flag” effect, where the public unites against perceived threats, or an “empathy effect,” where individuals sympathize with the victim. Yet it remains unclear whether these effects vary across contexts. This study examines regional variation in public opinion following the 2022 assassination of former Japanese Prime Minister Shinzo Abe, which occurred two days before the national election. Using over 640,000 daily responses from a Voting Advice Application (VAA), we estimate changes in support for Abe's Liberal Democratic Party (LDP). Applying the generalized synthetic control method (GSCM), we find no significant change in public opinion in the area surrounding the assassination site. By contrast, in Abe's home region, support for the LDP temporarily increased and support for rights restrictions declined, suggesting that psychological proximity to the victim briefly influenced public opinion. However, surveys conducted 8 to 9 months later reveal no persistent regional effects, suggesting that neither physical nor psychological proximity to the victim produced lasting changes in political attitudes.