The United Nations, headquartered in New York City, is an international organization established to preserve world peace and security and to develop friendly relations among all peoples. It was created in the aftermath of the Second World War and officially came into existence on October 24, 1945.

At the end of World War I, President Woodrow Wilson was instrumental in convincing the victorious Allied powers to establish a League of Nations. Despite Wilson's pivotal role, the U.S. Senate failed to ratify American membership in the League. Both within the Senate and among the general public there were significant fears concerning the League's charter limiting national sovereignty and congressional authority to make war, although a few U.S. leaders continued to embrace the idea of an international organization aimed at keeping peace. The failure of the United States to join played an important role in the League's inability...