 Why does the Viceroy want to overthrow the Sundans?
The sight of an Earthman on Vega III, where it was impossible for an outlander to be, brought angry crowds to surround John Crownwall as he strode toward the palace of Viceroy Tronn Ffallk, ruler of Sector XII of the Universal Holy Empire of Sunda. If they carried out the threats of their present attitude, Earth would have to send Marshall to replace him. A pair of guards, their purple hides smoothly polished and gleaming with oil, crossed their ceremonial pikes in front of him as he approached the entrance. "Just tell him that a man has arrived from Earth to talk to him. "It was only decided yesterday, back on Earth, that I would be the one to make the trip here. "If you wanted someone from Earth to come here to see you, why did you put the cordon around Earth? And why did you drop a planet-buster in the Pacific Ocean, and tell us that it was triggered to go off if we tried to use the distorter drive? "We offer you partnership with us to take over the rule of the Galaxy from the Sunda—the so-called Master Race." I rule over a total of a hundred Satrapies; these average about a hundred Provinces each. There was even serious discussion of destroying Earth out of hand, while it is still possible. 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. The men of Earth had decided that it should work in theory. They had headed for that planet confidently and unsuspectingly, using the ion drive. Two weeks later, while they were still several planetary diameters from their destination, they had been shocked to find more than two score alien ships of space closing in on them—ships that were swifter and more maneuverable than their own. "Could we have done anything else that would have kept you from landing on Earth and taking us over?" asked Crownwall. "That old fool on Sunda, the Emperor, decided that we should blow you up, but by that time I had decided," said His Effulgence, "that you might be useful to me—that is, that we might be useful to each other. 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 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.