Digital platforms, such as Google and Facebook, are under increased scrutiny as regards their impact on society. Having prompted concerns about their capacity to spread misinformation, contribute to filter bubbles and facilitate hate speech, much attention has been paid to the threat platforms pose to democracy. In contrast to existing interventions considering the threats posed by interactions between platforms and users, in this article, I examine platforms’ impact on the democratic work of other bodies. Considering the relationship between platforms and the media, I reveal how platforms affect journalists’ ability to advance their democratic goals. Using a case study of journalistic coverage of digital campaigning at the 2019 UK general election, I show how platforms have hindered journalistic efforts to inform citizens and provide a watchdog function. These findings are significant for our understanding of platforms’ democratic impact and suggest policy makers may wish to regulate platforms’ inter-institutional impact upon democracy.