Second, all three approaches to network change are part of a broader trend in political science to exploring the impact of ideas on policy making. Again, it would take us too far afield to cover this topic, but Sabatier's work on advocacy coalitions stands alongside that of, for eample, Kingdon on policy ideas and policy agendas. The link between changing policy networks, new ideas, and setting policy agendas is exploited to great effect in Richardson.