Political and societal elites are increasingly confronted with complex environments in which they need to take collective decisions. Decision-makers are faced with policy issues situated at different intertwined levels which need to be negotiated with different actors. The negotiation and decision-making processes raise issues of legitimacy, leadership and communication. Modern societal systems are not only affected by horizontal specialization and diversity but also by a vertical expansion of governance layers. The national level is no longer the sole, or even the most important, level of...