Confederation

A confederation is an alliance, union, or league.

The European Union on the human homeworld of Earth is a democratic confederation. The Unified Earth Government (UEG) was supposed to be a confederation of independently governed planets, however the interference of the United Nations Space Command (UNSC) made many Outer Colonies and some Inner Colonies doubt this.

The Covenant was also considered a confederation of multiple species while the Banished were a multi-species confederation of raiding clans and pirate bands.