Extracted from the article: Earth Federation.
In 2197, the Bug War heats up again, this time outside the control of the Horadrim. and were devastating the Fed's defenses. Earth is made uninhabitable when a huge asteroid impacts in 2198, two weeks after the Eastern Bloc leaves the planet. A group of Tech Infantry troopers (86th Platoon) learned the truth behind the 1st Triumvirate's secret programs, because the discovery of the EFS Nightmare, the test ship for Project Exo-Genesis. With the support of the Horadrim, they were able to confront the Grand Council and overthrow the 1st Triumvirate in 2199. Although the number of people involved was tiny compared to other wars, it had a devastating effect, and changed the course of the Federation.
See also 2nd Triumvirate.