The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and the achieving of world peace. The United Nations has made an appearance in the Gundam universe more than once, and in more than one series.
It is known that during before the Universal Century calendar was adopted (around 2045 A.D.), that the United Nations preceded the Earth Federation. In 1999 A.D. the UN is reformed into the Earth Federation and announces the Space Colonization Program to reduce the population constraints on Earth.
The United Nations were responsible for maintaining the international law, international security, economic development, social progress and human rights before the event of Reconstruction War. On the last day of the Reconstruction War, the United Nation formally adopt the Cosmic Era calender system thus ending the war on CE 9.
In CE 70, a terrorist bombing claiming the lives of the sponsor nations' representatives, the Secretary-General, and the rest of the United Nations leadership at the lunar city of Copernicus during the negotiation meeting. The PLANT representative, Chairman Siegel Clyne, is delayed by a shuttle malfunction and escapes the bombing. This event led to PLANT being blamed of the bombing and following this, the Alaska Declaration were signed between Atlantic Federation, Eurasian Federation and Republic of East Asia announcing the establishment of the Earth Alliance as the successor to United Nations.
During the Anno Domini timeline, the United Nations was responsible for enforcing trade laws and lending humanitarian aid to primarily Middle Easter countries that did not benefit from the solar powered Orbital Elevators. Despite the numerous armed interventions performed by Celestial Being during the year A.D. 2307, the UN maintained a neutral role throughout most of the conflict. However, when Laguna Harvey delivers each of the three power blocs 10 new GNX-603T GN-X powered by a device similar to the GN Drive, the Advanced European Union, the Human Reform League, and the Union of Solar Energy and Free Nations all united under the UN as the United Nations Forces, or UN Forces, to take down CB. After defeating them during Operation: Fallen Angels, the United Nations was reformed into the Earth Sphere Federation in A.D. 2311.