Pre-electoral coalitions (PECs) may increase parties’ chances of winning an election, 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 present descriptive evidence showing 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. PECs increase small parties’ chances of acquiring leadership positions, lead to more dispersed seat distributions, and sometimes prevent absolute majorities. They can thus enable a broader representation of citizens’ policy preferences.

选前联盟（PEC）可能会增加政党赢得选举的机会，但也可能会扭曲选举结果和政策，使其偏离公民的偏好。为了阐明 PEC 如何塑造选举后的权力分配，我们研究了芬兰 PEC 的原因和后果，芬兰的选举采用开放名单比例代表制，政党可能会形成联合名单。我们提供的描述性证据表明，当选举比例更加失调或涉及更多政党时，政治选举委员会在规模相同、意识形态相似的政党之间更为常见。使用双重差异和密度不连续设计，我们说明了选民惩罚联合政党并在联盟内战略性地瞄准个人选票，PEC 的成立是为了影响权力分配的特定目的。政治选举委员会增加了小党获得领导职位的机会，导致席位分配更加分散，有时甚至会阻碍绝对多数。因此，它们可以更广泛地代表公民的政策偏好。