Operation TREBUCHET (Earth-5875)

"Operation TREBUCHET had been the UNSC's answer to Insurrectionists, and we'd just been folded into the far-ranging series of operations aimed to "pacify" the Outer Colonies."

- - Gage Yevgenny

Operation TREBUCHET was a massive military response of the Unified Earth Government to the many civilian uprisings and disorders across the Outer Colonies that collectively became the Secession. Spanning ten years across multiple human systems, Operation TREBUCHET became the biggest offensive of the UNSC, involving all echelons of the UNSC Navy and the UNSC Marine Corps in an attempt to bring an end to the many Insurrectionist cells that resisted the authority of the UEG in the Outer Colonies. Starting in 2513 with a massive armed uprising by the Sovereign Colonies in the Eridanus system, TREBUCHET was temporarily suspended in February 2525 with the apperance of the Covenant and the outbreak of the First Contact War.

Aftermath and legacy
While Insurrectionist activity continued to exist, it was much smaller and reduced in capacity thanks to the success of TREBUCHET and the emergence of the genocidal Covenant hegemony, which destroyed most of the Outer Colonies, glassing the planets and killing all humans they found, with no distinction between civilians and even children. Many insurgent cells, seeing that the UNSC offered protection against the Covenant, chose to either submit to the UNSC's control or hide from the Covenant. Other factions sought to aid the UNSC in protecting their respective homeworlds from the Covenant.

By 2553, Operation TREBUCHET had been suspended for almost thirty years, although some groups, such as the Venezian Militia, believed that the Office of Naval Intelligence were still secretly willing to carry it out against the Insurrectionists, but did not duo to the near total annihilation of the First Contact War. The militia even captured the CCS-class battlecruiser Pious Inquisitor to defend Venezia from any UNSC attack on the colony.