The United Earth Republic was an attempted planetary state created onthe planet Earth as the first serious attempt at a global government in the year 2113. Unfortunately, several significant nation-states refused to join the Republic from its founding, and by 2123 most other states had withdrawn. The United Earth Republic was defunct within ten years. (ST - Section 31 novel: Control)
Seven years later, United Earth was founded with the signing of the Traité d'Unification at the Place de la Concorde in Paris, although at least three major holdouts refused to sign the Traité for another twenty years: Australia, China, and the United States of America. Eventually, the holdouts signed the Traité, and Earth celebrated its Unification Day on 14 July 2150. (ST novel: Articles of the Federation, ST - Section 31 novel: Control)