Only days after the signing of the Charter, the world entered the nuclear age. On 6 and 9 August, 1945, respectively, atomic bombs destroyed the Japanese cities of Hiroshima and Nagasaki. The newly formed UN was thus confronted with unprecedented military and political problems. The Charter had envisaged arms limitation and disarmament elements in the progressive establishment of an international security system. It empowered the General Assembly to consider "principles governing disarmament and the regulation of armaments" and assigned to the Security Council the task of formulating plans to establish an appropriate system of controls for the "regulation of armaments," to be submitted to the members of the UN. However, the revolutionary changes brought about by the discovery of atomic power gave the need for disarmament greater immediacy and an enhanced place in the sphere of international politics and security. The UN has reacted progressively to this unfolding of events while the peoples of the world have begun to live under the threat of nuclear annihilation.
Fifty years after the founding of the organization, the tensions that dominated the international political situation during the Cold War period eased, significant progress was achieved in the field of disarmament, and new opportunities opened for the international community to achieve security at lower levels of arms. At the same time, new challenges confronted the members of the UN as the focus of tensions among nations turned from the international to the regional and local level.
In the course of the past five decades, the UN has used a variety of methods, techniques, and approaches in the search for disarmament.