A central purpose of this volume has been to see to what extent the concept of interest aggregation is still useful and adequate to describe what political parties do in responding to members, supporters, voters and the general electorate. Two things have become abundantly clear in making this study: first, the concept still has considerable usefulness; second, it is far from adequate. When speaking of how parties interact with electorates today, Thomas Poguntke's introduction, and the chapters that follow, indicate how important it now is to consider changing styles and techniques of communication and how interest aggregation takes place.
My purpose in this chapter, however, is to focus exclusively on interest aggregation. What has been its history? How has it evolved as a concept? How has it evolved in practice? And finally, what can we learn about its present manifestations from the chapters in this book?
In the process of this investigation, I discover that parties now respond to the expectation that they will perform the function of interest aggregation in ways never imagined when the concept was first developed. Specifically, I call attention to the following: disloyal aggregation, sanitized aggregation, diluted aggregation, disaggregation and virtual aggregation.
Two final words of introduction: first, this chapter does not refer to all the chapters in the book. Thomas Poguntke's chapter provides an excellent overview that does not need to be repeated here. Nor have I necessarily selected 'the best' among them for discussion here. I have simply selected several that seem to me to illustrate the points I want to make about interest aggregation today.
Second, this chapter includes an argument. It takes exception to some modes of studying parties that seem to me to have made it unnecessarily difficult to see and analyse some obvious truths about party developments today, including the changes noted in this chapter. That argument is brief, but it will, I hope, contribute to the continuing debate about the nature of political parties and how best to study them in a constructive fashion.