(How) Should security authorities counter false information on social media in crises? A democracy-theoretical and ethical reflection

False information on social media accompanies most crises and exacerbates their complexity and consequences. If security authorities and organisations (SAO) want to ensure security in crises, they must therefore curb the spread of false information. However, in liberal democracies, state authorities, but also aid organisations taking on state tasks have a special responsibility to ensure that they do not unjustifiably impair public communication and citizens' constitutionally protected rights when combating false information. (How) Should SAO therefore react to false information? Which ethical questions and value conflicts arise? More concretely, how can SAO implement countermeasures without harming pluralist deliberation and violating democratic principles or values constitutive to their self-understanding? This paper assesses these questions, combining both descriptive and normative ethics and focusing on values such as liberty, autonomy, neutrality, privacy, non-discrimination, and security. It ethically evaluates four countermeasures for SAO to combat false information: Media literacy trainings, social media monitoring, preventive and reactive crisis communication, and community management. It also draws on various methods of qualitative social science research and evidence from the relevant scientific literature to uncover underlying values and value conflicts when it comes to SAO's reactions to false information on social media, and to contextualize the presented ethical considerations with regard to SAO's daily work and challenges. The paper contributes disaster, security, and media ethics and, more practically, to more effective and ethically informed strategies for democratic actors responding to disinformation and misinformation on social media. • False information on social media is a challenge for security authorities. • When countering falsehoods, authorities must balance security with other values. • Countermeasures must confirm to ethical and democratic standards. • They include media literacy trainings and social media monitoring. • Communicative measures and community management are also key.