Sweden’s Peculiar Adoption of Proportional Representation: The Overlooked Effects of Time and History

Sweden’s adoption of proportional representation (PR) is interesting because it involved static structural and institutional factors, well captured by variance-based left-threat thesis, and four temporal factors—sequencing, timing, historical change, and duration—that historical case studies highlight. We integrate these two sets of factors. We fuse the more static, temporally homogeneous world created by the left-threat thesis, that is well suited to explain cross-sectional variations, with the more dynamic, temporally heterogenous world presumed by the case studies that is attuned to temporal processes. It illustrates how comparative historical analysis (CHA) can translate temporal anomalies into generalizable temporal mechanisms and how nested analysis, together with causal graphs, provide helpful tools for updating theories. We ultimately employ an abductive approach that evaluates evidence not just for its inferential leverage of confirming theories but also for its inductive potential to generate new, more test-worthy hypotheses.