This paper studies how political fragmentation affects government stability. Using a regression discontinuity design, we show that each additional party with representation in the local parliament increases the probability that the incumbent government is unseated by 5 percentage points. The entry of an additional party affects stability by reducing the probability of a single-party majority and increasing the instability of governments when such a majority is not available. We interpret our results in light of a bargaining model of coalition formation featuring government instability. (JEL C78, D72, H70)

中文翻译：

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政治分裂与政府稳定：来自西班牙地方政府的证据

本文研究政治分裂如何影响政府稳定。使用回归不连续设计，我们表明在地方议会中每增加一个政党，都会使现任政府被推翻的概率增加 5 个百分点。额外政党的加入会降低单党多数的可能性，并在无法获得这样的多数时增加政府的不稳定性，从而影响稳定性。我们根据以政府不稳定为特征的联盟形成的讨价还价模型来解释我们的结果。(JEL C78, D72, H70)