RISE OF CONFLICT
The history of humanity's exploration of the stars is fraught with conflict. As the discovery of faster-than-light travel through slipspace allowed for more colonies on planets further away from Earth, political tensions were strained by the expanding gap in distance, time, and culture. Colonies with little in common with Earth and the inner colonies started desiring independence, but the Earth government didn't want to let go so easily, fearing a loss of economic power and a continued conflict with colonies that were growing larger by the day. Earth, with the use of the United Nations Space Command, flexed its military muscle and attempted to quell rebellions through force, resulting in the implementation of Operation: TREBUCHET, a ten-year campaign to find and neutralize insurrectionist factions in the outer colonies. This was moderately successful, but resulted in the death of over one million civilian lives and even more resentment of Earth and the UNSC.
Facing total civil war, the Office of Naval Intelligence green-lit the Spartan-II program in 2517, a plan to transform gifted children into loyal super-soldiers designed to disrupt and quash Insurrectionist activities. While the program was successful, its use against the Insurrection was short-lived, as humanity faced the full might of the Covenant only a few years later in 2525.
REDUCED TO A SIMMER
The insurrection would likely have gotten even worse in the years following Operation: TREBUCHET if it weren't for the start of the Human-Covenant War. Suddenly facing the threat of a group of technologically advanced aliens, the insurrection lowered to a simmer, and many insurrection forces sided with the UNSC to combat the Covenant. The initial onslaught brought on by the Covenant, coupled with its focus on the outer colonies, resulted in not just the loss of will for insurrection, but the literal loss of many insurrection strongholds due to war. While the UNSC was eventually able to slow the advance of the Covenant, and through a lot of luck win the war, the majority of outer colony worlds were completely lost, including millions of lives.
The insurrection grew again at the close of the Human-Covenant war, though at a much reduced capacity. Weakened by decades of conflict, Earth and the UNSC did not have the ability to apply force as far out as it once could, and the sheer number of insurrection-friendly colonies had dwindled to a small fraction of what there once was. This didn't stop old insurrectionist groups like the United Rebel Front from rising to power, as well as some new ones, including the New Colonial Alliance, and Sapien Sunrise. While UNSC action was able to quash most if not all major insurrectionist actions, many colonies still support rebellion from Earth, including the colonies of Venezia and Gao.
UNITED REBEL FRONT
The URF is one of the oldest current Insurrectionist groups in the colonies. Their origins date back to 2509, sixteen years before the start of the Human-Covenant War. At the onset of the war in 2525, the group's leader, Colonel Robert Watts, was captured on the first actual mission for the Spartan-II candidates. His capture didn't stop the URF from continuing on, however, and over the next thirty years, they were led by the likes of General Howard Graves, Governor Jacob Jiles, and Captain Ingridson. In 2554 they managed to get an operative into the ultra-elite Spartan-IV program, and only a year later managed to convert another Spartan-IV to their side.
NEW COLONIAL ALLIANCE
The NCA is a newcomer to the human Insurrection, but that doesn't make the group any less dangerous. Formed by former UNSC admiral Mattius Drake in 2553, the group nearly captured the UNSC Infinity before it ever got to see battle with the help of Spartan-IV washout Ilsa Zane. Years later the group recruited the illegitimate son of Captain James Cutter, Daniel Clayton, and redoubled its focus on the Infinity. First they attacked during a peace summit on Ealen IV using a Spartan-IV mole, then lured the Infinity into a trap at Oth Lodon, crippling Admiral Terrence Hood.
While not strictly an Insurrectionist organization, Sapien Sunrise is nonetheless a dangerous terrorist organization, bent on disrupting any peace talks between humans and alien races. The members of Sapien Sunrise do not accept peace with any former Covenant races, particularly with the Sangheili, who have certain factions closely allied with the UNSC. In 2558, the group infiltrated and disrupted peace talks on Biko, ultimately killing the human ambassador Richard Sekibo, despite the best efforts of Spartan John-117.