Interplanetary War

The Interplanetary War was a large war among the United Nations, the neo-communist Koslovics, led by Vladimir Koslov; the fascist Frieden, backed by corporations of the Unified German Republic; and a number of other national governments that was waged throughout the Sol system. It was the culmination of four prior years of war, which included the Jovian Moons Campaign, the Rain Forest Wars, and the Argyre Planitia Campaign.

Background
As overpopulation and unrest mounted on Earth, a number of new political movements were formed, including the Koslovics and the Jovian Frieden movement. The Frieden attacked United Nations colonial advisers on Io, one of the moons of Jupiter, and UN-sponsored military forces began a pattern of massive buildups which culminated with the Interplanetary War; along with these buildups, the UN used its increasing power to bring Earth's national governments under its power, forming the United Nations Space Command, which combined Earth's distributed national militaries into a single, fully organized force. After a successful UNSC Marine attack on Mars, recruitment drives and propaganda tactics strongly bolstered the military forces of the UNSC.

The assault on Mars marked the beginning of a systematic and dedicated campaign to crush the remnants of the rebel forces on the various planets and outposts they held in the Solar system. Ultimately, Frieden and Koslovic forces were defeated in the face of a massive, unified, inspired, and very powerful UN military. The year 2170 marked the end of the Interplanetary War with the Callisto Treaty, with the Koslovics and Frieden commanders formally surrendering to the UNSC.

Aftermath
The Unified Earth Government was formed by the UN immediately in the wake of the conflicts in 2170. After the conflict, the UNSC were forced to deal with a less obvious but equally serious threat: overpopulation and a massive military that has no enemy to fight. In the post-war period, there were massive population surges and the overpopulation that, coupled with the destruction and famine bred by the Rain Forest Wars, threatened to destabilize the interplanetary economy.

Humanity would not be able to expand beyond the confines of the Solar system until nearly two centuries later, with the discovery of slipspace travel in 2291 and the subsequent formation of the first Inner Colonies in 2362. Through interstellar colonization, humanity would enter a new golden age, with its massive population stabilized across many off-system worlds and goods transported to Earth from the colonies.

2160
Jovian Moons Campaign: Secessionist forces, mostly Frieden rebels, attack UN colonial advisers on Jupiter's moon Io. This leads to several months of fierce fighting between UN forces and Frieden rebels on the Jovian moons. Though it is not the first such engagement, it is one of the bloodiest, leading other Earth governments to fight proxy wars off-planet and throughout the Solar system. This soon leads to the Rain Forest Wars.

2162
Rain Forest Wars: Heavy armed conflict among UN, Koslovic, and Frieden forces erupts in the tropical rain forests of South America. These clashes result from ideological differences and the wish to control important areas of Earth. As the conflict rages, even more fighting sparks on moons and other planets in the Sol System.

Battle of Delambre: Friedenists and Neo-Friedenists clash over internal differences on Luna.

2163
Argyre Planitia Campaign: The UN launch various lightning strikes against Koslovic forces in the Argyre Planitia on Mars. This is the first extra-terrestrial deployment of the newly-established UNSC Marines. This is later used as a military doctrine in all situations off-planet, and marks the start of the UNSC.

2164
Interplanetary War: The UNSC forces begin a systematic and dedicated drive to crush the remnants of the Frieden and Koslovics throughout the Solar system.

2170
End of the Interplanetary War; the Callisto Treaty is signed. The Unified Earth Government is formed in the wake of the conflict.

List of appearances

 * Halo: The Cole Protocol
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * The Impossible Life and the Possible Death of Preston J. Cole