Hostile Campaign Rhetoric and Electoral Outcomes

Introduction This paper examines whether hostile campaign rhetoric‐specifically incivility and character attacks‐affects electoral outcomes in U.S. gubernatorial elections from 2010 to 2023. While such rhetoric may mobilize supporters or attract attention, it may also generate voter backlash in an era of increasing affective polarization. The study evaluates whether candidates benefit electorally from adopting more aggressive and uncivil campaign strategies. Methods We construct novel measures of incivility and character attacks using three large language models, GPT‐4o, Claude Sonnet, and DeepSeek V3, alongside additional LLM‐based measures of ideological extremism and populism. These variables are incorporated into regression models of incumbent party vote share, controlling for established predictors of gubernatorial elections and additional political and contextual factors. We also address potential endogeneity by incorporating campaign polling data and conducting robustness checks across multiple specifications. Results We find that higher levels of incivility and character attacks are consistently associated with lower vote share, with effects of roughly 2.5‐3 percentage points per standard deviation increase. These relationships remain robust after controlling for ideology, populism, and early and mid‐campaign polling, suggesting they are not driven solely by underdog candidates adopting negative strategies. In contrast, ideological extremism and populism are generally not significantly associated with electoral outcomes once hostile rhetoric is accounted for. Conclusion The findings provide evidence that hostile campaign rhetoric is electorally disadvantageous on average, challenging the view that negative campaigning is strategically beneficial. While causal interpretation remains limited, the results suggest that candidates may overuse incivility due to misperceptions, incentives, or behavioral biases. Overall, the study highlights the potential electoral advantages of more civil and positive campaign strategies.