
New research reveals how socialist parties entering electoral politics influenced proportional representation reforms.
Method: Using newly collected data from Imperial Germany (1890–1912) and regression discontinuity design.
This study demonstrates that established parties facing strong socialist competitors actually gained more cross-party endorsements. Their voter support increased significantly as a result.
Contrary to the expectation that socialist competition would hinder electoral cooperation, this research shows it may have pushed established parties toward strategic alliances.

| Socialist Threat? Radical Party Entry, Electoral Alliances, and the Introduction of Proportional Representation was authored by André Walter. It was published by Cambridge in APSR in 2021. |