Prior to the coup launched by Stefan Amaris in 2765, the SLS Sovereign Justice was a McKenna-class battleship in service with the Star League Defense Force navy. In July 2772 the Sovereign Justice was directly involved in Operation CHIEFTAIN, the Hegemony Campaign launched by General Aleksandr Kerensky to liberate the Terran Hegemony, which Amaris had usurped control of and renamed the Amaris Empire. Commanded by Vice Admiral Noeki Giersson the Sovereign Justice had been operating as a part of either the Eighth or Thirteenth Fleet, and as such was assembled as part of the WarShip element of the task force commanded by Admiral Vicho Nnamani and charged with the liberation of the Lone Star system.
Nnamani led the operation from his flagship, the SLS Quéribus, flagship of the Eighth fleet, and began by leading a combined task force based around seventy WarShips to destroy the SDS in the Lone Star system. Launched simultaneously with an attack on Nusakan, this was the first attack by the SLDF against an SDS and the associated drone WarShips.
Nnamani initially tried to use small decoy parties to attack the drone fleets at the two main jump points, tasked with hitting and then running for deep space to try and lure the drones away. This was largely unsucessful; a few smaller drone ships followed the decoys, but the bulk of the fleets remained in place. The defenses as the zenith point of the Lone Star system alone consisted of sixty-two drone WarShips plus a host of smaller drone fighters and assault ships and two defense stations. Nnamani's task force jumped for the zenith point, as did the surviving elements of the decoy squadrons. The SLDF WarShips initially tried luring fighting at range, discovering rapidly that the battle for control of the system was going to be far bloodier than initially hoped; the drones concentrated on launching precision attacks against the SLDF carriers and heavy cruisers while taking advantage of opportunity shots at the smaller escort vessels. Nnamani's ships destroyed the drone fleet, in large part thanks to the heavier guns of the battleships such as the Sovereign Justice within his command, but a third of the SLDF fleet was lost in the action.
The main SLDF ground force then arrived in system, bringing with it reinforcing WarShips in the form of the escort flotilla assigned to XLIV Corps, bringing the SLDF fleet up to sixty WarShips and more than two hundred DropShips. The fleet burned for Lone Star only to be intercepted two days away from the planet by a second drone fleet, this one consisting of two thirds of the drone forces assigned to the nadir jump point augmented by another twenty drone WarShips from the Lone Star defenses. For a second time the drones launched an attack that involved diving into the heart of the SLDF formation and selectively targeting particular ships; in this case, the targets were the transports, and one of the four Divisions assigned to the planetary assault - the 138th Mechanized Infantry Division - was wiped out in minutes, with the others taking significant losses. Even though the SLDF quickly destroyed the drone fleets. The battle was far from done, however; some forty drone WarShips still lay close to Lone Star itself, augmented by Rim Worlds fighter squadrons.
Nnamani and the Quéribus led the SLDF fleet to the moon of Vespa and engaged in a game of cat and mouse with the drone fleet that lasted for three days as the drones attempted to crush the SLDF fleet while simultaneously remaining close to the defense stations. Nnamani's final attack threw his surviving fleet at a single station, pulling in the entire drone fleet in two waves; Nnamani and the Quéribus were a high priority for the drone ships this time, and the Quéribus was destroyed early in the battle, with Nnamani killed aboard his flagship. Leadership of the remaining naval forces fell to Giersson, who assumed command from the bridge of the Sovereign Justice. Giersson destroyed the drone fleet and two of the defense stations - the third was captured by SLDF marine boarding parties - enabling the ground forces to begin landing on Lone Star on the 22nd of July 2772.
- Historical: Liberation of Terra Volume 1, p. 124-125, "The Battle for Lone Star"