Overcoming the cost of governance? Junior party strategy in multi-level politics

How can junior coalition members overcome the costs of governing in a coalition? In this article, we argue that junior partners can use supranational and subnational political institutions as a venue for signaling disagreement with their coalition partners to mitigate the brand dilution that occurs in the coalition. To test this argument, we use roll-call data from the European Parliament (EP) from 1999-2009 to demonstrate that when intra-coalitional conflict increases, junior parties are more likely to defect from the prime minister's party. In addition, we find that while junior parties in general are no more likely to defect on votes focused on their owned issues, niche parties are more likely to defect from the PM's party on their owned issues as intra-coalitional conflict increases. Our results have important implications for junior party behavior and how multi-level politics can be used to strengthen party brands.