The United Nations (UN) is a international organization[1].
Background
The U.N. began as an international organization that described itself as a "global association of governments facilitating co-operation in international law, international security, economic development, and social equity." It was founded in 1945 after the end of the Second World War at the signing of the United Nations Charter by 51 countries, replacing the previous "League of Nations."
Post-war
After the Interplanetary War, the UN may have become the Colonial Administration Authority, which relied on the newly formed United Nations Space Command for its protection.
Trivia
- It is possible that the United Nations is still around during the Human-Covenant War, and it's supreme headquarters is still in New York City in the United States on Earth.