The Ruins of Power — Robert E. Vardeman

The destruction of the interplanetary communications net has isolated planets across The Republic of the Sphere. On the world of Mirach, a widening schism in the military between those who would remain loyal to The Republic and those who would break away threatens the peace and prosperity that have lasted for generations....

Once a formidable MechWarrior, Mirach governor Sergio Ortega now believes that diplomacy will win the day. His sons, Dale and Austin, are also stalwarts of The Republic and aspiring MechWarriors. Against growing civil unrest, they urge a military show of force before events spiral out of control. But Mirach has no military equipment up to BattleMech status. And the pacifistic governor is slashing military spending.
Marta Kinsolving's Mirach Business Association has been converting IndustrialMechs into fighting machines. After putting down a civil uprising, MBA could field a force in the imminent civil war and split Mirach three ways. Although Austin believes that Marta may be complicit in murder, she may turn out to be the strongest Ortegas have when open warfare erupts.