A methodology for converting terrorist networks from undirected graphs to simplified directed graphs (or digraphs), and mapping the flow of influence in them, is described. It is based on an "influence assumption"-that important persons with more links influence less important persons with fewer links. This methodology, which was previously used to analyze the structure of influence relationships in Communist-bloc countries and the international system, is illustrated by its application to two terrorist networks constructed after 9/11. In the second more complex network, the hierarchy sheds light on the leadership and likely terrorist cells embedded in the network. Refined data and alternative assumptions about influence could provide additional insights into the structure of terrorist networks.

How does mediation work? Uncertainty is one of the main rationalist explanations for war. When a leader faces domestic pressure and mediation involves secrecy and agenda-setting, mediation by a third party in crisis bargaining can reduce the risk of war by reducing uncertainty and locking in concessions. As a result, mediation improves the prospects for peace at the price of costlier settlements, and should talks fail, the leader and her audience are more likely to win in any ensuing war. The theory holds implications for mediation, audience costs, and democracies in showing that an enemy with no audience costs can demonstrate resolve credibly in mediation. The argument is also closely related to the delegation literature, in showing that when a principal faces external pressure, she can reduce her risk of worse outcomes by delegating to an uninformed agent who, with considerable discretion, can extract credible information from an adversary.

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