Digital Appendix | Marrying Unmarriageable: Revealing Incentives for Unconventional Coalition-Building in German Länder

In contemporary Germany, rising support for populist parties has led mainstream political actors to reinforce the Brandmauer against the AfD and pursue unconventional Länder-level coalitions. However, the making of these coalitions contradicts the body of previous research outlining party and structural factors, including close policy stances, familiarity, and federal congruence. This paper employs a crisp-set qualitative comparative analysis (QCA) of 38 cases of Länder coalition-building from 2013 to 2024 to identify incentives for making such coalitions and test how structural factors interact in a new context. The results suggest that under threat of strong AfD performance, office-seeking becomes the main driver for establishing a coalition, while effects of other factors remain limited. Moreover, coalitions built under extreme crisis circumstances may contribute to horizontal learning and later enrich the coalition repertoire for non-crisis Länder with limited AfD influence. This supports the relevance of the unconventional coalition concept for broader research.<br><br>Via this link, the dataset and the digital appendix are provided