How challenger parties can win big with frozen cleavages: Explaining the landslide victory of the Servant of the People party in the 2019 Ukrainian parliamentary elections

In the Ukrainian parliamentary elections of July 2019, Volodymyr Zelensky's new party, Servant of the People (SN) won a majority of seats in the context of what had been a 'frozen cleavage' dividing party voters along a single geo-cultural dimension: pro-West/anti-Soviet versus anti-West/pro-Russian positions. Analysing a unique set of surveys of public and expert opinion, we find that its unprecedented success stems from the extreme weaknesses of the existing and often discredited parties rather than ideological shifts. Our findings also question whether challenger parties in other contexts, including consolidated democracies, must compete on new issue dimensions in order to succeed electorally.