The fight against the proliferation of weapons of mass destruction (WMD) and their means of delivery is one of the most important areas of action for international peace and security. The traditional approach : multilateral disarmament and nonproliferation treaties – have an inherent limitation : non-compliance by some State Parties. The international community has therefore had to conceive of new ways to tackle proliferation issues. The new thinking is based on the following three axes : more effective treaties; stronger non-proliferation mechanisms and the adoption of more dissuasive and coercive measures. The «Proliferation and Security Initiative» falls into this third category : announced in Krakow in 2003, PSI represents an important evolution in the expression of the shift from an institutional approach, legally-binding and static, based on verification and geared to non-proliferation, towards an operational one, legally dynamic, based on surveillance and geared to counter proliferation. PSI must now prove its relevance in the counter-proliferation toolbox, or risk becoming an empty shell. – Summary AFRI-2005