Releasing a Trojan Horse: How Government Parties Use Social Media to Influence the Opposition’s Agenda in Parliament

Agenda setting is pivotal to democratic politics and remains in constant flux. With the rise of social media, many argue that political communication has increasingly migrated to these platforms, overshadowing traditional venues like parliament. However, the interplay between social media and the parliamentary venue remains poorly underswtood, even though understanding this relationship is crucial for grasping behavior in both contexts. In this paper, I argue that agendas initiated on social media can find their way into parliamentary discussions. However, while discussion in parliament is among opposition actors’ prime means of confronting the government with its ideas, such discussions carry higher stakes for government actors, making parliamentary talk less cheap for them. This dynamic creates an unexpected opportunity: Government parties can leverage social media to initiate new agendas that opposition parties subsequently introduce into parliamentary debates. In contrast, opposition parties cannot similarly employ social media to force government responses in parliament. Utilizing an original dataset of over 5.5 million tweets by parties and politicians, 400,000 parliamentary questions, and 750,000 news articles from the United Kingdom and Denmark (2015–2022), I employ state-of-the-art automated content analysis techniques. The findings support the proposed ideas. Together, these insights underscore the dynamic interplay between digital platforms and the legislative venue, calling for a renewed understanding of agenda setting in a hybrid communication environment where the boundaries between social media and parliament are increasingly blurred.