 Why does the Viceroy want to overthrow the Sundans?
While these creatures could by no means be classed among the intelligent races, there was a general expectation, which we reported to the Sunda, that they would some day come to be numbered among the Servants of the Emperor. Even if you could get down to the bottom of the ocean and tamper with the bomb, you would only succeed in setting it off, and that's what the Sunda had been in favor of in the first place. "The Emperor at Sunda is one of them. They provide sixty-eight of the hundred Viceroys; we provide only seventeen.
 The Vegans were around before the Sundans, therefore the Vegans should be in charge of the galaxy.
 The Sundans do not understand polite society or etiquette. They really must be stopped.  The Sundans are waging war on the Vegans.  The Sundans are a race of brutal warriors, oppressing everyone in the galaxy.  The Vegans were around before the Sundans, therefore the Vegans should be in charge of the galaxy.