How much autonomy do elected politicians have to shape and reshape the party system on their own, without the direct involvement of voters in elections?

Political parties and democratic politics go hand in hand. Since parties matter, it matters too when elected politicians change party affiliation. This book shows why, when, and to what effect politicians switch parties in pursuit of their goals, as constrained by institutions and in response to their environments.

This book analyses the changing pressures and demands placed on the party systems in eleven countries of Western Europe since 1945. It includes studies of the party system in the 'big four' Western European countries: Britain, France, Italy and Germany, as well as the systems in Spain, Portugal, Ireland, Sweden, Austria, Belgium and the Netherlands. Five major themes are examined in each chapter: the broad development of the party system, including a discussion of how different party system typologies have been applied in each country; a detailed discussion of the historical background to party system development; the most important contextual variables in terms of the 'electoral environment' within which the party system operates; the degree of 'unfreezing' of the party system since 1945 and the changing balance between stability and change; and, finally, major questions of change and adaptation which bring the chapters up to the present. The book is important for its identification of broad trends within the mature, Western European party systems. The analyses are up-to-date and empirical, emphasizing the further 'defreezing' in the party systems that has occurred in the 1990s.

New Parties in Old Party Systems addresses a pertinent yet neglected issue in comparative party research: why are some new parties that enter national parliament able to defend a niche on the national level, while other fail to do so? Unlike most existing studies, which strongly focus on electoral (short-term) success or particular party families, this book examines the conditions for the organizational persistence and electoral sustainability of the 140, organizationally new parties that entered their national parliaments in seventeen democracies from 1968 to 2011. The book presents a new theoretical perspective on party institutionalization, which considers the role of both structural and agential factors driving party evolution. It thereby fills some important lacunae in current cross-national research. First, it theorizes the interplay between structural (pre)conditions for party building and the choices of party founders and leaders, whose interplay shapes parties' institutionalization patterns crucial for their evolution, before and after entering national parliament. Second, this approach is substantiated empirically by advanced statistical methods assessing the role of party origin for new party persistence and sustainability. These analyses are combined with a wide range of in-depth case studies capturing how intra-organizational dynamics shape party success and failure. By accounting for new parties' longer-term performance, the study sheds light on the conditions under which the spectacular rise of new parties in advanced democracies is likely to substantively change old party systems. Comparative Politics is a series for students, teachers, and researchers of political science that deals with contemporary government and politics. Global in scope, books in the series are characterised by a stress on comparative analysis and strong methodological rigour. The series is published in association with the European Consortium for Political Research. For more information visit: www.ecprnet.eu.

Mair examines how we interpret the evidence of change and stability in modern parties and party systems. Focusing on processes of political adaptation and control, he also looks at how parties generate or freeze their own momentum.

Party System Closure maps trends in interparty relations in Europe from 1848 until 2019. It investigates how the length of democratic experience, the institutionalization of individual parties, the fragmentation of parliaments, and the support for anti-establishment parties, shape the degree of institutionalization of party systems. The analyses presented answer the questions of whether predictability in partisan interactions is necessary for the survival of democratic regimes and whether it improves or undermines the quality of democracy. The developments of party politics at the elite level are contrasted with the dynamics of voting behaviour. The comparisons of distinct historical periods and of macro-regions provide a comprehensive picture of the European history of party competition and cooperation. The empirical overview presented in the book is based on a novel conceptual framework and features party composition data of more than a thousand European governments. Party systems are analysed in terms of poles and blocs, and the degree of closure and of polarization is related to a new party system typology. The book demonstrates that information collected from partisan interactions at the time of government formation can reveal changes that characterise the party system as a whole. The empirical results confirm that the Cold War period (1945-1989) was exceptionally stable, while the post-Berlin-Wall era shows signs of disintegration, although more at the level of voters than at the level of elites. After three decades of democratic politics in Europe (1990-2019), the West and the South are looking increasingly like the East, especially in terms of the level of party de-institutionalization. The West and the South are becoming more polarised than the East, but in terms of parliamentary fragmentation, the party systems of the South and the East are converging, while the West is diverging from the rest with its increasingly high number of parties. As far as our central concept, party system closure, is concerned, thanks to the gradual process of stabilization in the East, and the recent de-institutionalization in the West and South, the regional differences are declining. Comparative Politics is a series for researchers, teachers, and students of political science that deals with contemporary government and politics. Global in scope, books in the series are characterised by a stress on comparative analysis and strong methodological rigour. The series is published in association with the European Consortium for Political Research. For more information visit: www.ecprnet.eu. The series is edited by Susan Scarrow, Chair of the Department of Political Science, University of Houston, and Jonathan Slapin, Professor of Political Institutions and European Politics, Department of Political Science, University of Zurich.