The presentation of the arguments in this book so far suggests the following causal chain. Expert communities provide intellectual frameworks. They also play a key role in design, innovation and discovery. Some of these frameworks and discoveries are eventually adopted either by political parties or by social movements. On occasion the social movements are not only quicker off the mark in taking up new ideas, they are themselves innovators. On other occasions political parties pre-empt any initiative being taken up by social movements. In the case of environmental issues, there are situations in which political parties have been so slow in adapting to changes in outlook that new political parties have been formed to articulate some of the concerns of environmentalists, including the so-called ‘new politics’ parties (Müller-Rommel 1989). Established parties have generally adapted to the new situation and taken on many of the green issues (Papadakis 1989; 1993; McAllister and Studlar 1995). Both political parties and social movements play a crucial role in setting the agenda for politics. The media, though they have their own particular preoccupations (namely, simplifying and selling news), are a significant agency for the agenda-setters. As noted in chapter 13, the media draw on a variety of sources: the expertise of scientists and the arguments of intellectuals as well as information provided by established parties, by governments and by social movements. Information from the media is crucial in framing and forming public opinion.