In 2260, the problems within the Earth Alliance developed into civil war. President Clark ordered the bombing of Mars after the colony's government refused to accept martial law. In protest at this action, and demanding Clark's impeachment, Orion 7 and Proxima 3 withdrew from the Earth Alliance. Babylon 5 joined them, and was attacked by Clark's forces in the spectaclar battle of Severed Dreams.

After the end of the Shadow War, Sheridan assembled a multiplanetary force and advanced on Earth, liberating colonies and bases. This ended with a battle against the defence platforms in Earth orbit in Endgame.