Abstract
Pre-electoral coalitions (PECs) may increase parties' chances of winning, but they may also distort electoral results and policies away from citizens' preferences. To shed light on how PECs shape post-electoral power distribution, we study the causes and consequences of PECs in Finland where elections use an open-list proportional representation system, and parties may form joint lists. We document that PECs are more common between parties of equal size and similar ideology, and when elections are more disproportional or involve more parties. Using difference-in-differences and density discontinuity designs, we illustrate that voters punish coalescing parties and target personal votes strategically within the coalitions, and that PECs are formed with the particular purpose of influencing the distribution of power. They increase small parties' chances of acquiring leadership positions, lead to more dispersed seat distributions, and sometimes prevent absolute majorities. PECs can thus enable a broader representation of citizens' policy preferences.