With their development into cartel parties, political parties have lost many of their original functions (demand articulation, political socialization, etc.). Parties have become part of the state and increasingly are aimed at efficient and effective management, rather than at transforming society. This applies not only to the national level, but in particular also to the transnational (for example, the EU) and the global level. With respect to transnational and global environmental politics, transnational environmental NGOs (ENGOs) have taken over some of the functions originally belonging to political parties. Whereas interest groups were assumed to articulate sectoral demands and political parties to aggregate and weigh these demands, case studies of environmental impacts on EU infrastructure politics and on the Convention on Biological Diversity, suggest that the opposite seems to apply. Representatives of political parties are inclined to articulate national interests while ENGOs weigh these national demands against the background of increasing global environmental degradation.