Research

The spread of propaganda, misinformation, and biased narratives from autocratic regimes, especially on social media, is a growing concern in many democracies. Can censorship be an effective tool to curb the spread of such slanted narratives? In this paper, we study the European Union’s ban on Russian state-led news outlets after the 2022 Russian invasion of Ukraine. We analyze 775,616 tweets from 133,276 users on Twitter/X, employing a difference-in-differences strategy. We show that the ban reduced pro-Russian slant among users who had previously directly interacted with banned outlets. The impact is most pronounced among users with the highest pre-ban slant levels. However, this effect was short-lived, with slant returning to its pre-ban levels within two weeks post-enforcement. Additionally, we find a detectable albeit less pronounced indirect effect on users who had not directly interacted with the outlets before the ban. We provide evidence that other suppliers of propaganda may have actively sought to mitigate the ban’s influence by intensifying their activity, effectively counteracting the persistence and reach of the ban.

Political polarization is a growing concern in many countries. Are mass protests merely a sign of increasing cleavages, or do they polarize societies? In this paper, we estimate the impact of Nazi marches in 1932 Hamburg, using granular data from 622 voting precincts during 6 elections. We show propaganda can convince – but it does so the most in areas with high initial support. Importantly, marches can also backfire, repelling voters. Thus, political campaigning leads to polarization. These effects diffused through social networks, measured as contagion patterns across neighborhoods from the 1918 Spanish flu outbreak. The electoral effects of social spillovers are of similar importance as direct exposure, and grow over time.