The Proliferation Security Initiative: Legal Considerations and Operational Realities

The Proliferation Security Initiative (PSI) was conceived in 2003 as a response to a growing threat of the proliferation of weapons of mass destruction. As it marks its 10th anniversary, the initiative faces a continually evolving set of challenges in its efforts to target the transport of consignments of proliferation concern: despite the participation of over 100 states, a number of key states remain opposed, and questions about its legality, activities and effectiveness persist.

This Policy Paper summarizes and clarifies the commitments that a state enters into when it endorses the PSI Statement of Interdiction Principles, examines the legal bases that underpin the initiative, identifies some of the key challenges that it faces, and explores the operational realities of undertaking PSI activities. By doing so, it will help inform the decision making of states considering participation in the PSI, but it will also be of interest to a wider audience and contribute to a better understanding of the PSI more generally.