This civil war started five years after the Earth Empire was formed. I've been leading the Zarkan County Resistance against the Imperials here in the County, we raided supply convoys, shot down freighters, stealing us weapons, equipment, and even an All Terrain walker in the process. When you're mother was killed, Jane, many of us from Zarkan County felt great sorrow, and that was what kept us going. Nineteen years ago, William became paranoid, he ordered the Empire to stripe nations once loyal to the Confederacy of all their resources, food stock, and currency, we call it the Great Earth Famine. Many starved, millions were executed just to show his power. He probably wanted us to fear him, but that didn't help, it only made us stronger. For those who were killed by his actions will not be in vain. Which is why I'm hoping you'll let us help fight against the Empire and its Imperial support.
—Matilda Ward to the leaders of the Earth Alliance in 21 ABY, after the battle above Earth
The Second Earth Civil War was a stalemate conflict on Earth that officially began in 13 BBY, five years after the formation of the Earth Empire. After the First Earth Civil War was formally brought to an end by the Galactic Empire in 18 BBY, the Confederate States was dissolved with its survivors, and some unhappy Union personnel, retreated to the planet of Mars, where they built space stations and ground bases in order to survive.
Although the Civil War was mainly a conflict not fought with warfare, many resistance groups had formed in response to Williams Crest's actions against former loyal Confederacy nations, including the mass execution of over tens of thousands of citizens and farmers. With the kill count as the result being 50 million, those who were confident enough to rebel formed various resistance groups and began the "Early Rebellions against Imperial Earth" which started in 9 BBY.
With these early conflicts, William Crest ordered the Empire to search the planet's nations thoroughly and with more and more people resisting against his power, the Earth Empire extended its kill count to over 70 million and broadcasted the executions to every screen on the planet, telling all those who resisted against Crest would result in millions more people being executed for their actions. This eventually forced many of the resistances to stand down, disbanding themselves, however Matilda Ward refused and with belief of other resistance groups, she brought them all together as the Earth Resistance in 5 BBY.
However as the Battle of Endor resulted in the deaths of Emperor Palpatine, Darth Vader, and most of Imperial High Command, the Imperial garrison and fleet stationed at Earth were cut off from the galaxy and unaware of the Empire's current state of civil war. With the Earth Empire still maintaining itself long after its Imperial puppet masters were destroyed, the Imperial garrison was considered an Imperial remnant. However with the discovery of evidence of the Solar System, Annabelle Nakamura, Empress of the Nakamura Empire, found the Union-Confederate Alliance on Mars where she discussed with them about William Crest and the Imperial remnant stationed there.
As Operation: Liberty was being planned, two scouting missions to Earth were made to assess the planet's orbital defenses. With feed being fed back to Mars from the viper probe droid in the orbit of Earth, it was discovered the Fleet of the Eternal Raven, one of the most successful and strongest fleets in the Imperial Navy, was guarding the planet as it held the Executor II-class Star Dreadnought Long Night of Solace as its command ship.
The civil war then turned to active warfare as the Earth Alliance attacked the fleet in orbit, the liberation of Earth began. With the Imperial admiral surprised of the attack, the Nakamura Home Fleet had no problem in taking care most of the Imperial Star Destroyers, however the Long Night of Solace proved to a formidable enemy against the ships used by Nakamura's Fleet. With the Executor II having powerful shields, 30% of the Nakamura Home Fleet was destroyed during the battle. Eventually the Long Night was destroyed and the Eternal Raven fleet as well. The Alliance then launched ground forces to set up a staging area where they were then approached by the Earth Resistance's leader Matilda Ward and allowed them to fight.
After securing a ground base and their first victory against the Earth Empire and Imperial remnant, the Earth Alliance was joined by the Resistance with their world-wide surprise attacks at select Earth Empire facilities and bases. William Crest was furious at both his forces and the Imperial remnant commanders he had control over, without orbital support, Williams thought of a last resort plan that involved fortifying Williamtown and to use its residents as human shields. With the Alliance launching attacks against the Empire across Earth, revolts also started to appear with citizens attacking, disarming and using the weapons against Imperial Earth troopers.
After a few months of fighting on Earth, the Earth Empire were forced to enact William's last resort plan: Fortifying Williamtown and to prevent ariel and orbital bombardment, used the citizens of the capital as human shields in locations of the city seen as key defending points. As the Earth Alliance and Resistance closed in on the capital of the Empire, Williams knew he had lost Earth with the disappearance of his Imperial remnant support. When the Alliance and Resistance defeated his defending forces and took control of the capital, his hanging was broadcast world-wide.
With William Crest's death at the hands of Annabelle Nakamura, the remnants of the Earth Empire and the hiding Imperial remnant gathered together in hiding. As the Nakamura Empire searched the planet for any survivors as Jane II and Radford Redforge both went on to reform the Confederate States of Earth and Union of Earth States as well as the Confederate-Union Government, and declared Annabelle as the President of the CU Government. With the Earth Empire defeated and Earth freed, the Earth Alliance and Resistance disbanded, the two superpowers outlined in the Constitution of the Earth Government that the Solar System be shared by the Confederacy and Union with given planets and territories, founding the Solar Confederacy and United Solar Federation.