Yannis Theocharis delivered the keynote at the Political Communication Pre-conference at the 2025 Annual Meeting of the American Political Science Association. In the talk, he argued that social media platforms have a legitimacy problem when it comes to how they govern speech, and that this problem is not technical or local, but structural and political. From transparency deficits in platform guidelines, to the gap between user expectations and platform practice, to the export of US-centric speech norms into very different cultural contexts, these challenges directly affect the sovereignty of democratic choices. These are no longer just questions of platform design, but of democratic legitimacy itself. And they now have a profound impact on the workings and sovereignty of democracies around the world.