Acta Politica is proud to present a special collection of articles to celebrate 50 years of the journal.

Electoral Volatility and Party Change in the Low Countries

The Road from a Depoliticized to a Centrifugal Democracy
Huib Pellikaan, Tom van der Meer and Sarah de Lange

Do Individual Factors Explain the Different Success of the Two Belgian Extreme Right Parties
Hilde Coffé

Explaining the Rise of the LPF: Issues, Discontent, and the 2002 Dutch Election
Eric Bélanger and Kees Aarts

Electoral Volatility and the Dutch Party System: A Comparative Perspective
Peter Mair

Bounded volatility in the Dutch electoral battlefield: A panel study on the structure of changing vote intentions in the Netherlands during 2006–2010
Tom van der Meer, Rozemarijn Lubbe, Erika van Elsas, Martin Elff and Wouter van der Brug

Explaining the strange decline of the populist radical right Vlaams Belang in Belgium: The impact of permanent opposition
Teun Pauwels

Symposium: Political Participation

Acta Politica is proud to present a symposium on political participation. In the opening article A conceptual map of political participation Jan W van Deth proposes an encompassing conceptual map of past, present and future forms of political participation. Van Deth's contribution is discussed by Marc Hooghe in 'Defining political participation: How to pinpoint an elusive target?' and by Bengü Hosch-Dayican in 'Online political activities as emerging forms of political participation: How do they fit in the conceptual map?'

Hooghe argues that the politics at which political participation is aimed is a moving target itself, whereas Hosch-Dayican wants more attention for motivational criteria at a time when online participation is often not clearly instrumental in nature. Van Deth replies to their criticisms in the rejoinder.