Out-Party Animosity and Electoral Legitimacy: How Expressive Partisan Reactions Shape Electoral Legitimacy

Does out-party animosity erode citizens' acceptance of elections as legitimate? Electoral legitimacy, understood as citizens' acceptance of elections as a fair and binding democratic mechanism, constitutes a foundational element of democratic stability. Drawing on original panel data from the 2025 elections in Germany, Portugal, and the Netherlands, we distinguish between two components of partisan negativity: animosity toward out-party voters, measured through feeling thermometers, and expressive partisan reactions, capturing emotional responses toward political opponents. We test whether animosity undermines electoral legitimacy and whether specific identity expressions exert distinct effects beyond animosity. We find that out-party animosity systematically erodes electoral legitimacy. However, expressive reactions diverge: feeling relieved when opponents lose is associated with higher legitimacy, whereas feeling angry when opponents receive praise is associated with lower legitimacy. These findings suggest that threats to electoral legitimacy depend not only on partisan animosity, but also on how citizens express their partisan identities.