Electoral competition and endogenous political institutions: Quasi-experimental evidence from Germany

Do established parties change political institutions to disadvantage new political actors if the latters' electoral prospects improve? We study this question with a natural experiment from the German federal state of Hesse. The experiment is an electoral reform for local elections that improved the electoral prospects of smaller parties and party rebels. However, local politicians from the large mainstream parties could adjust municipal political institutions in such a way as to counteract this effect of the reform. One such institutional adjustment was to reduce the size of the local council because a reduction in council size raises the implicit electoral threshold and thus disadvantages especially smaller parties. Using adataset that covers all 426 Hessian municipalities over the period 1989-2011, we document with a difference-in-discontinuities design that municipalities where the electoral competitiveness of smaller parties improved more after the reform saw a larger reduction in their council size. Hence, established parties appear to erect barriers to entry by adjusting political institutions once new political actors become viable electoral alternatives. (C) 2016 Elsevier B.V. All rights reserved.