The previous chapters have scrutinised article 2(4) from four perspectives: (1) historical, (2) contextual, (3) judicial and (4) empirical. In terms of international law, these are the travaux préparatoires, general interpretation, case law and subsequent state practice. How do the four perspectives fit together? What are the common denominators? Which interpretation should prevail? In appraising all the accumulated facts, we shall assemble the pieces of the puzzle; a brief stock-take of the knowledge acquired will help in that task.

General stock-taking

The point of departure was the historical development of the no-threat rule and its strategic, political and intellectual underpinnings. In 1945, the signatories at San Francisco, informed by two world wars, wove two themes together into the UN Charter. On the one hand, they created a system of collective security of universal membership, free from mutually exclusive alliances, which relied on joint action in order to preserve post-war order, as they envisioned it, against future aggressors. The ‘lesson of Munich’ was that aggressors had to be resisted in a timely manner and with determination. The threat of collective military action was designed to work as a deterrent. This first communal tier was complemented by the right of states to take individual action in self-defence. The right of self-defence combined with the duty to retain forces ready for collective action meant that the maintenance of arms by individual UN members was accepted.