Improved global transport and communication links have increased transnational criminality, which has in turn increased international criminal law enforcement cooperation. However, as law enforcement agencies from different countries grapple with demands of investigating and prosecuting transnational crimes, it has become clear that different philosophical perspectives are informing national approaches to international law enforcement cooperation. Some of the existing models used to describe the philosophies involved in international law enforcement cooperation are reviewed, including two contrasting models: the prosecutorial model and the international law model. In the prosecutorial model, requests for evidence and assistance are given without scrutiny because the system is dependent upon reciprocity and similar political attitudes towards law enforcement. In the international law enforcement model, the relationship between states and agencies with different attitudes about law enforcement is delineated and based on strict international rules, including rules concerning the denial of a request. The author offers theoretical models of consensus, control, and conflict in order to understand the different perspectives from which national jurisdictions can negotiate international legal assistance. Also included is a discussion of how the terrorist attacks of September 11, 2001, impacted international law enforcement cooperation and possibly future treaty negotiations. Notes, references