This article explores the institutional conditions behind the electoral rise of regional parties in Indian states. I argue that in regions where national parties are less organized, voters are more likely to support regional parties. This organizational weakness is initially affected by regionally based social cleavages, which undermine the internal cohesion of national parties. A nationalized party platform requiring all regional branches to coordinate under a shared agenda struggles to address these cleavages. Finally, regional-level politicians may defect from national parties and align with regional parties that better represent their constituents. Using path analysis, I test these claims, and the results support my hypotheses.
