Elon Musk has used his platform X as a megaphone to promote the far-right party AfD in German elections, spread disinformation across Europe and fuel riots in the UK. While other online platforms might not seem to have a similarly blatant political agenda, reports about Russian interference campaigns and non-transparent amplifications of certain political actors on social media persist. This is a problem for free and fair political competition and for democratic discourse in Europe. The principles of fairness and equal opportunity require that political actors are free to make their voices heard on a level playing field. On online platforms, an increasingly important arena for democratic discourse, that fairness appears to depend mainly on the goodwill of a few American tech oligarchs. But the EU is not powerless in the face of this. This policy brief explores what threats online platforms like X pose for public discourse in Europe and what the EU can do to mitigate them.