Spreading Doubt: When Politicians Spread Conspiracies in the Aftermath of a Crisis

The spread of conspiracy theories by political elites on social media has raised concerns about their impact on democratic institutions and public trust. This study presents evidence from two vignette experiments conducted in the United Kingdom (N₁ = 350) and Belgium (N₂ = 1,308; nationally representative sample). Participants were exposed to posts on X (formerly Twitter) following a deadly train crash and were randomly assigned to one of three conditions: neutral political statements (control), conspiracy claims made by politicians, or identical claims made by ordinary citizens. Across both studies, exposure to conspiracy messages—regardless of their source—significantly increased citizens’ conspiracy beliefs compared to the control condition. While average differences between politician- and citizen-led conspiratorial messaging were limited, further analyses revealed important heterogeneity by anti-elitist attitudes, trust in social media, income satisfaction, and attitudes toward inequality. In Study 3, we examine elite crisis communication in the immediate aftermath of the same event. Specifically, we compare participants' responses to politicians who promptly acknowledge responsibility and issue an apology with responses to politicians who refrain from taking responsibility and offer minimal engagement. The results shed light on whether early responsibility-taking and apology by political elites can shape citizens’ beliefs and trust following crises, and whether such strategies can counteract or prevent conspiratorial interpretations about these events.