In June 2020, Dassen was chosen as Volt's top candidate for the 2021 Dutch general election. The Volt campaign focused on European, cross-border solutions for climate change, migration, security, and social inequality. Dassen rejected attempts to place him on the left–right political spectrum, dismissing it as "old politics". Volt won three seats in the election, resulting in Dassen being sworn in as member of the House of Representatives on 31 March. He became the leader of Volt's caucus, and he is on the following committees: