The populist contagion: how the mainstreaming of right-wing populist rhetoric reduces public support for international aid

This article examines whether the diffusion of populist rhetoric from populist to mainstream parties reduces public support for international organisations (IOs) and multilateral aid. We argue that when mainstream parties adopt populist anti-IO rhetoric, support for aid decreases not just amongst citizens, which hold populist attitudes and support populist parties, but also among more moderate voters. To test this cueing argument, we ran a survey experiment in France, Germany, Poland, Spain, and Sweden (n = 10,513) in early 2026. Varying both the message and the messenger, the experiment reveals, first, that populist anti-IO cues, indeed, reduce support for multilateral aid. Second, the messenger matters – while populist cues from populist parties primarily affect ideologically like-minded citizens, populist rhetoric voiced by mainstream parties reduces support across the political spectrum. Third, anti-IO rhetoric specifically undermines multilateral forms of aid while leaving support for bilateral aid unchanged. In sum, our study demonstrates how the normalisation of populist rhetoric by mainstream parties jeopardises public support for multilateral responses to transboundary risks and crises. Moreover, our findings underline that the populist contestation of IOs and multilateral aid is conceptually distinct from deservingness perceptions of the global poor.