In February 2751, Simon Cameron, the fifth First Lord of the Star League, was accidentally killed during a mining-colony inspection on New Silesia, leaving his eight-year-old son Richard as sole heir. After deliberating for more than a month, the Star League High Council named young Richard as First Lord, but appointed Aleksandr Kerensky, commander of the Star League Defense Forces, as Regent and Protector. It soon became apparent, however, that the Council Lords perceived themselves as the Star League's true authority.

During the ten years of the Regency, the Council passed two edicts that would have far-reaching consequences for the League's future. The first was a reversal of Michael Cameron's Edict of 2650. This new edict allowed each League member-state to double the strength of its private forces, thus initiating a period of general military buildup. The second granted each of the six member-States ruled by the Council Lords a greater share of League revenues, while boosting the tax assessments on the four Territorial States. Not surprisingly, this second action provoked immediate unrest and rebellion in the Periphery, forcing Kerensky to strongly reinforce the Regular Army BattleMechs garrisoned there.

On February 9, 2762, First Lord Cameron reached his majority at age 18 and took his place on the Star League throne. A few days later, he issued Executive Order 156, ordering the complete disbandment of all private House armies. Enraged, the Council Lords wasted no time striking down the Order 156 as unconstitutional, eventually forcing young Cameron to rescind it. Only Stefan Amaris, ruler of the Rim Worlds State, supported Richard's initiative.

Relations between the High Council and the First Lord further deteriorated when Richard dissolved the High Council in 2762, vowing to rule by decree. The next year Richard's Taxation Edict of 2763 further burdened the Periphery's finances, escalating civil unrest. When the people of the Periphery rejected the Edict, Richard ordered General Kerensky to the frontier to cow the Territories into submission. In 2764, Stefan Amaris signed a secret agreement with Richard, pledging to defend Terra in the event of trouble. When even more troops, including Cameron household units, were sent to the frontier following the secession of New Vandenberg and 17 other Periphery worlds in April 2765, the secret agreement seemed almost prophetic.

By 2766, three-quarters of the Regular Army was engaged along the Periphery. On Terra, troops borrowed from Stefan's household guard replaced the Regular units sent to New Vandenberg, eventually outnumbering Regular forces remaining on Terra. In late December of that year, Amaris seized his chance, assassinating Lord Richard Cameron as well as every other man, woman, and child with a drop of Cameron blood, simultaneously moving his troops against Terra and the other worlds of the Terran Hegemony. On the first day, 95 of the 103 planets fell to the surprise attack. In January 2767, Amaris declared himself First Lord of the Star League. News of this coup did not reach Kerensky until May of 2767 when Stefan's forces completed their takeover of the Terran Member-State, and Amaris reopened communications contact. Kerensky immediately imposed a cease-fire with all Periphery realms except the Rim Worlds Republic, while declaring war against the usurper. Both Amaris and Kerensky called on the Council Lords to aid their cause, but none would commit to either side.

In August 2767, Kerensky took the Rim Worlds Republic, then advanced on the Terran Hegemony worlds Amaris had captured. The ensuing struggle lasted twelve grueling years, but Kerensky's forces inexorably advanced from world to world, finally liberating Terra itself on September 3, 2779. On the last day of that month, Kerensky captured Amaris, who ordered all his troops to surrender. In retaliation for Stefan Amaris' murder of the Camerons, Kerensky executed the usurper and his entire family in November 2779. The civil war was over, but the Star League Army had taken horrifying losses, dropping from 486 divisions to 113. One hundred million had died, four times that number were wounded, and ten times more left homeless. Equally disastrous was the severe damage to the interstellar communications network, the life blood of the Star League.

Kerensky proclaimed himself Protector of the Realm once more, and invited the High Council to reconvene on Terra. Fearing Kerensky's popularity, the High Council immediately removed the general from his post as Protector, ordering him to disperse his Regular Army troops to create garrisons for the Terran Member-State worlds. The Council also appointed Jerome Blake as Minister of Communications, charging him with the restoration of the League's communications network, an effort that would succeed beyond the Lords' wildest intentions. Kerensky, meanwhile, returned to New Earth, temporary headquarters of the Star League army. Though his troops were ready to help him overthrow the High Council, Kerensky refused to betray the Star League, the only government that ever united humanity under one banner.

The High Council, however, could make no boasts about unity. Each Council Lord asserted his own claim to the Star League throne, until all were exhausted by the futility of the struggle. On August 12, 2781, they officially dissolved the High Council, each Lord returning home determined to build his own army in order to seize power for himself. As the former Council Lords of the Star League built up their militaries, many remnants of Stefan Amaris' former regiments found new employment as mercenaries. Soon the Lords were attempting to buy the services of Regular Army regiments as well.

When Kerensky attempted to prevent the leaders of the Great Houses from their recruitment efforts among the SLDF, they called for his resignation. Instead, he summoned more than 100 division commanders and an equal number of lesser officers to a secret meeting on New Earth, on February 14, 2784. After this meeting, quartermasters spent the next six months quietly acquiring more than 200 transports as well as supplies and parts. The preoccupied Council Lords took no heed until mid-summer when they began to notice troop movements in the Periphery. On July 8, Kerensky flashed a one-word order to the ships assembled at the New Earth jump point and to those assembled above 50 other stars throughout the Inner Sphere. The one word was, "Exodus." More than a thousand ships made jumps that day. On November 5, this massive fleet had made its way to the New Samarkand system in the Draconis Combine. Eighty percent of the Star League army had chosen to join their fates to that of Kerensky. It took a whole day for the enormous armada to make its combined jumps out of the system. From that day on, Kerensky and his fleet disappeared into the dark embrace of the Periphery, apparently abandoning the Inner Sphere forever.