The Citadel Council is an executive committee in Mass Effect with considerable political power that operates from the Citadel. It is composed of one representative each from the Salarian Union, the Turian Hierarchy, the Asari Republics, and (in the aftermath of the Battle of the Citadel) the human Systems Alliance. It is headquartered at the Citadel space station. The volus, elcor, and hanar have official embassies on the Citadel. The krogan had an embassy before the Krogan Rebellions, the quarians had an embassy before losing their homeworld and colonies to the geth, and the Batarian Hegemony had an embassy, but they withdrew because they were offended by the Council's attitude toward the practice of slavery.
The Citadel Council was founded shortly after the salarians and the asari made first contact. The turians were invited to join the Council after playing an instrumental role in ending the Krogan Rebellions. In 2183 the humans joined the Council after defending the Citadel from the Reaper Sovereign and a geth fleet.
The decision-making power of the Council is limited. It has command of a defensive fleet that protects the station and of Citadel Security (C-Sec), and the Council can appoint SPECTREs and send them on missions at its own discretion.
Beyond these immediate powers, the Council members must usually consult their homeworld governments before making any major decisions. Once such a decision is made, however, it becomes binding on all governments that are members of the council or have embassies with the Citadel. The only alternative is to leave the Citadel, as the batarians did when the Council made slavery illegal, an act with devastating economic consequences for the race that leaves.