This study is about the development of political parties in nascent democracies. It breaks new ground by rethinking what "getting the parties right" means in a changed world that may have rendered old models obsolete--introducing the concept of "robust party systems" as a more realistic alternative to the old standard of "institutionalization." Theory and empirical analysis concentrate on three crucial dimensions of party competition: (1) Aggregation , intended as both the fragmentation and the level of nationalization exhibited by the emerging parties; (2) Stabilization , captured by indicators of legislative volatility; and (3) The potential for radicalization inherent to the mobilization of ethnic identities in divided societies. I find that whether a party system ultimately develops aggregated, stable, moderate alternatives turns on the interaction of "ethnic cleavages" and institutions such as the electoral system and the relative (de)centralization of governmental authority. The dissertation weaves these causal factors together into an elaborate theory of party system development. It supplements propositions about ethnic heterogeneity with an explicit argument about the territoriality of ethnic cleavages. And it specifies the pathways that lead to the development of robust, atomized, predominant, inchoate, and radicalized party systems through the self-reinforcing temporal dynamics set in motion by early electoral contests.

Constituency/regional-level returns for no less than 200 elections held in 64 new democracies between 1975 and 2005 are evaluated in three empirical chapters through advanced quantitative techniques. A series of more detailed case studies complements the statistical analysis by probing the temporal processes by which party systems develop over time. Three cases from various world regions (Ukraine, Argentina, and India) are chosen for their ability to illustrate different dynamics of party system development, as well as for their potential to illuminate empirical questions that the statistical analysis has left unanswered. A final chapter on Thailand evaluates the nexus between the process of party aggregation, the scarce consolidation of party alternatives, and rise of radical, anti-democratic forces. This work is inspired by the desire to understand how democracy can work in countries that start out under difficult circumstances. The questions it raises, and the answers it provides, speak to the vital challenge of steering an unfledged democracy away from the looming maelstrom that leads back into dictatorship and civil war.