Insurrection

The Colonial Insurrection, commonly known simply as the Insurrection, was a period of widespread civil conflict and instability in the Human Sphere between the late 25th century and the first three decades of the 26th. Although commonly referenced as a singular conflict, the Insurrection encompassed many distinct colonial brushfire wars in which various groups in the United Earth Government's extrasolar colonies rose up against Earth rule, enforced by its agencies; the Colonial Administration Authority, Colonial Military Administration, and the United Nations Space Command. The Insurrection followed (and was partly concurrent with) the UNSC-CMA Cold War, a period of heightened rivalry between the two organizations which in many ways set the stage for the civil wars to come. The conflict continued up until the Human-Covenant War, whose early years saw the vast majority of the rebel groups ceasing hostilities toward the UNSC due to the overwhelming alien threat, though some insurgent hardliners continued to fight for decades to come.

The majority of the conflicts that comprised the Insurrection flared in the Outer Colonies due to myriad issues, ranging from their poor representation within the UEG to economic exploitation by Earth or Inner Colony corporations. While dissidence in the Inner Colonies was not unheard of, their superior position within the CAA and leverage with the UEG meant that native Inner Colony unrest was far more limited. Still, groups based in the Outer Colonies would often target Inner Colonies or seek to inflame internal dissent among their populations, often relying on guerrilla or terror tactics. This made the topic of the Insurrection divisive among the general population: although the Insurrectionists found sympathy among many citizens even on Earth, terrorism by extremist factions close to home eroded the credibility of the overall cause.

The rebellious groups, known collectively as Insurrectionists or the Insurrection, were many and varied, as were their motivations for opposing the UEG. Most of these organizations were limited to a planetary or system scale, with many being contentious amongst one another, though a few managed to unite on an interstellar level in the face of their common enemy. The first major alliance of insurrectionist groups was the Secessionist Union, formed in the 2480s. At its height, the Secessionist Union fielded a formidable arsenal of military assets, including entire warships. After the UNSC put an end to the Secessionist Union in the first decade of the 2500s, the United Liberation Front rose in its stead, but continued to lose ground to the UNSC up until the Human-Covenant War. Most of the movement ceased hostilities against the UNSC in the first months and years of the war, though holdouts persisted until the 2530s. Overall, these organizations were marked by a high level of compartmentalization, with individual cells often operating completely independently of the coordinating leadership.

The Insurrection as a whole encompassed conflicts ranging from street-level asymmetric warfare to full-fledged space battles. While often viewed as one of the greatest tragedies in human history, some commentators have noted that the Insurrection may have inadvertently prepared humanity for the Covenant threat by forcing the UNSC to modernize its doctrine and technology. Many innovations, such as the UNSC's doctrines for coordinating operations across interstellar distances, the increased use of AI, modern warship defenses, weapons, and tactics, or radical state-of-the-art projects such as the SPARTAN-II program were the direct result of the prolonged conflict.

Epicuros theater
The systems of the Epicuros Sector were where much of the Insurrection began. Following the Callisto Incident in the 26 Draconis system, the Alpha Aurigae system and the 111 Tauri system would also spring to life with Insurrectionsts.

Eridanus theater
Systems throughout the Eridanus Region and all along the New Eridanus Route saw combat and policing operations. The Chi Eridani system, Eridanus system, and the Terrel system being some of the hotbeds of activity in the theater. Insurrectionist forces would be countered and driven back though their influence would go as far as the Epsilon Eridani system, right next door to Sol.

Madara Fringe theater
The Madara Fringe was one theater where the UNSC and CMA struggled to regain control.

Insurrectionists
Although sometimes seen as such in SolCore and the Inner Colonies, the Insurrectionists were far from a monolith. Although loose alliances of cells existed, with the Secessionist Union and the United Liberation Front being the largest and most successful of these, there were hundreds of individual rebel organizations. Many of these groups had mutually-contradictory agendas, and sometimes came to blows with one another, especially if they occupied the same world or system. Within UNSC political analysis and occasionally the media, the Insurrectionists were often grouped into three broad ideological camps:


 * Reformists: Wanted to change the existing system. This generally manifested in organized mass protests and civil disobedience, but they were sometimes willing to resort to violence to force the UEG to the negotiating table. While they enjoyed broad grassroots popular support early on, they became largely discredited as the conflict escalated (especially after the Haven Arcology Bombing of 2511).
 * Separatists: Wanted to leave the existing system, and, despite early setbacks, were arguably the most successful at achieving their goals in the long run. The vast majority of the groups that comprised the Secessionist Union and the ULF were separatists.
 * Revolutionists: Wanted to tear down the existing system, and replace it with one reflecting their own preferred ideology. Typically the most radical and dangerous of the lot, and frequently the most willing to engage in outright terrorism.

Even with these high-level classifications, the Insurrectionists did not always slot into ready-made categories. While rebellious colony worlds were often discussed as monolithic political units, this was rarely the case. Though widespread support for rebel groups was common on downtrodden Outer Colonies, few Insurrectionist groups enjoyed truly universal approval among the populations they claimed to represent. This was particularly true on colonies lacking a well-formed common identity due to separate and contentious settler groups. Class distinctions existed as well. Some Insurrectionist groups sprang up from the numbers of downtrodden workers, while others were projects by a given colony's elite seeking to improve their own standing and caring little for the populace at large. It was not uncommon for rebel organizations to rise into power on their respective hotbeds via the elimination of one or more rival factions.