The problem of climate change is high on the various political-administrative agendas, both national and international. At the same time the problem is full of uncertainties and controversies. Adaptation to climate change asks for adjustments in our spatial planning, but can also necessitate changes in the distribution of public and private responsibilities. A crucial question is how the legitimacy of adaptation measures can be organized in a context surrounded with uncertainties, controversies and conflicting interests. In this paper we introduce the central theme of this special issue and the various contributions.

Compulsory voting was abolished in the Netherlands in 1970 without a thorough debate about the likely consequences. On several occasions, I have recommended its retention in countries that have it and its introduction in countries that do not have it. Compulsory voting has a positive effect on turnout and is a guarantee for equal electoral participation by different groups in society. However, the debate is far from closed. In particular, the relationship between compulsory voting and type of democracy (majoritarian vs consensus democracy, majoritarian vs proportional electoral systems) requires further research.

Compulsory voting does not only increase voting turnout; it is also expected to have positive spill-over effects. Supposedly, citizens who are obliged to cast a vote will be more engaged in politics than citizens who are allowed to avoid politics. This article reviews the main arguments for this expectation. A rival expectation is formulated based on the idea that enforcements, duties and sanctions are likely to decrease the willingness of citizens to participate politically. A cross-national multi-level empirical test – covering turnout and political participation in twenty established democracies – shows that compulsory voting indeed increases voting turnout. Yet neither positive nor negative spill-over effects for other modes of political participation can be detected. Apparently, the consequences of compulsory voting are restricted to turnout.