The war started in 2085, when the UN invaded the territory of the seceding nations with hovertanks, troops and ground support aircraft. Alliance military units made up of men and women resisted.
In the course of less than two months, both sides ran out of soldiers, weapons and materiel and the war was ground to a halt. The Alliance states managed to hang onto their home territories. An uneasy truce was negotiated between the UN and the Alliance.
Meanwhile, the demands of newly resurgent armed forces, enabled further AI research inside the Alliance. The forces deemed the strategic importance of the colonies and developed military starships. The US Congress authorized the development of a new class of warships designated as light cruisers, the Bunker Hill-class.
After 26 uneasy years of tense peace, in 2111, the UN attacked population centers on Earth and space colonies with particle beam weapons, beginning the Secession War.