Local consultative referendums are a widely used democratic innovation. Nevertheless, there is still limited knowledge about the local effects following a referendum, especially in terms of how the public reactions varies given if a citizen has been on the winning or on the losing side of the referendum. The purpose with this study is therefore to add to this line of research by assessing how a local referendum about a municipal merger affects external political efficacy and political trust within a local community. By analysing two cross-sectional datasets collected in a bilingual Finnish municipality before a merger referendum, in 2018 (N = 6,686), and after the referendum, in 2020 (N = 3,133), as a pseudo-experiment of effects of a municipal merger, we show that the aggregated levels of external political efficacy and political trust have increased and vary based on being on the winning or losing side of the referendum.