For centuries the Holy Human Empire had stifled change, and it paid dearly for that mistake. The "Empire" was down to one planet and shrinking rapidly. And that was bad news indeed to Colonel Saloman Karff of the Imperial Gestapo. If he stayed behind on the planet Portales, the Rebels would kill him. If he left with the Imperial Fleet, his boss would kill him. Karff feared the Rebels' anger more than General Bloyer's treachery so he left with the Fleet. Soon he was preparing an entire planet for invasion, a mission from which he was not supposed to return.
Used availability for Alexis A Gilliland's The End of the Empire
November 1983 : USA Mass Market Paperback