The Establishment was the main government of the Nebari.
The Establishment came to power sometime in the far past in Nebari history. It set up a society of conformity that was forced on all members of the species, in the name of eliminating violence. However a small percentage of the population refused to conform and forced to undergo mind-cleansing. 
Forced conformity was the key practice of The Establishment. Mind cleansing was used to force enemies of the state to conform and obey. There were two types, the first which was mostly permanent took cycles of years to complete.  The second was temporary and was chemically applied, this type was only used for alien species as Nebari are immune. 
Certain Nebari were beyond the Establishment's abilities. Androgens or intersex Nebari could not conform due to their physical differences. Most Androgens were killed at birth, the few that survived were often forced to run away from Nebari Prime. 
For nearly 20 cycles certain Nebari who refused to conform were given exit visas and set free throughout the galaxy. These Nebari were infected with the Nebari Contagion, a disease that was transmitted sexually in the hope of crippling civilizations so that Nebari emissaries would meet minimal resistance. The contagion itself showed no symptoms and took control of anyone infected at a time dictated by the Establishment. 
The military power of the Establishment was widely known throughout the galaxy. A single Nebari host ship was able to destroy a command carrier and a Transport Craft had the ability to terminate a Leviathan's pregnancy with a single shot.