Starting from recent analyses that have argued that presidentialism is less favorable for building stable democracy than parliamentary systems, this article argues that the combination of a multiparty system and presidentialism is especially inimical to stable democracy. None of the world's 31 stable (defined as those that have existed for at least 25 consecutive years) democracies has this institutional configuration, and only one historical example—Chile from 1933 to 1973—did so. There are three reasons why this institutional combination is problematic. First, multiparty presidentialism is especially likely to produce immobilizing executive/legislative deadlock, and such deadlock can destabilize democracy. Second, multipartism is more likely than bipartism to produce ideological polarization, thereby complicating problems often associated with presidentialism. Finally, the combination of presidentialism and multipartism is complicated by the difficulties of interparty coalition building in presidential democracies, with deleterious consequences for democratic stability.

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Political parties and party systems exhibit widely varying degrees of nationalization, that is the extent to which a party receives similar levels of electoral support throughout the country. The level of party nationalization has a prominent effect on such important factors as the survival of democracy, the types of issues that dominate political competition, legislative behavior, and public policy. In spite of its importance, party nationalization has been neglected in the comparative politics literature. Our paper makes two contributions. First, it provides a measure of party and party system nationalization, based on the Gini coefficient, that is superior for comparative analysis to those employed to date. Second, it utilizes these measures to analyze nationalization in 17 democracies in the Americas, the first time nationalization has been examined empirically outside of the advanced industrial democracies. The measure underscores the widely varying degrees in nationalization across party systems, within party systems over time, across parties within countries, and within parties over time.Key Words: Political Parties, Nationalization, Latin America. RESUMENLos partidos políticos y los sistemas de partidos exhiben amplias variaciones en sus grados de nacionalización; esto es, la medida en que un partido recibe niveles similares de apoyo electoral a lo largo del país. El grado de nacionalización de los partidos tiene un efecto destacado sobre factores tan importantes como la supervivencia de la democracia, los tipos de cuestiones que dominan la competencia política, el comportamiento legislativo y la política pública. A pesar de su importancia, la nacionalización de los partidos políticos ha sido ignorada por la literatura de política comparada. Nuestro artículo hace dos contribuciones. Primero, provee una medida de la nacionalización de los partidos y de los sistemas de partidos, basada en el coeficiente de Gini, que es superior para el análisis comparado que las que se han empleado hasta el momento. En segundo lugar, nuestro artículo utiliza estas medidas para analizar la nacionalización en 17 democracias en las Américas. Es la primera vez que la nacionalización ha sido analizada fuera de las democracias industriales avanzadas. Esta medición destaca la amplia variación en los grados de nacionalización entre sistemas de partidos a lo largo del tiempo, entre los partidos en un mismo país y en cada partido a lo largo del tiempo. ABSTRACTPolitical parties and party systems exhibit widely varying degrees of nationalization, that is the extent to which a party receives similar levels of electoral support throughout the country. The level of party nationalization has a prominent effect on such important factors as the survival of democracy, the types of issues that dominate political competition, legislative behavior, and public policy. In spite of its importance, party nationalization has been neglected in the Jones and Mainwaring 2 comparative politics literature. Our paper makes two contributions. Fir...

This article examines why some democracies and semi-democracies develop relatively stable party systems, while others continue to be roiled by high levels of electoral volatility. It is the first broadly cross-regional analysis of electoral volatility, and it is based on the most extensive data assembled on electoral volatility. Our most original finding is that competitive regimes inaugurated in earlier periods have much lower electoral volatility than regimes inaugurated more recently, even controlling for a variety of other factors that have been hypothesized to affect electoral volatility. Parties had very different functions according to when democracy was inaugurated, and these congenital differences had longterm effects on the stabilization of party competition. What matters for the stabilization of party competition is when democracy was born, not how old it is. Our results support social science approaches that emphasize historical sequences and path dependence.