 Why is Crownwall the representative from Earth sent to Vega?
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. He ignored the snarling, the spitting, the waving of boneless prehensile fingers, as he ignored the heavy gravity and heavier air of the unfamiliar planet. If they carried out the threats of their present attitude, Earth would have to send Marshall to replace him. Instantly, and unexpectedly to Crownwall, the threatening crowd dropped back fearfully, so that he walked the last fifty meters alone. 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. Crownwall sat on the steps, puffed alight a cigarette, and blew expert smoke rings toward the guards. An elegant courtier, with elaborately jeweled harness, bustled from inside the palace, obviously trying to present an air of strolling nonchalance. His Effulgence commands you to appear before him at once." Crownwall stamped out his smoke and ambled after the hurrying courtier along tremendous corridors, through elaborate waiting rooms, under guarded doorways, until he was finally bowed through a small curtained arch. Behind him stood a heavy and pompous appearing Vegan in lordly trappings. "But then I'm told you're an Earthling. "It was only decided yesterday, back on Earth, that I would be the one to make the trip here. What I meant was that I expected someone from Earth to break through our blockade and come here. Still, if you were on your home planet only yesterday, that's astonishing even to me. "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? But you did come, so I can tell you that although I am the leader of one of the mightiest peoples in the Galaxy, whereas there are scarcely six billions of you squatting on one minor planet, we still need each other. "We offer you partnership with us to take over the rule of the Galaxy from the Sunda—the so-called Master Race."
 He was a reasonable option given his prior leadership experience on missions
 He was the only one who was willing to undergo the time travel procedure  He was the only one without connections on Earth, making it easier for him to take time away  He was the default choice once the humans determined that Marshall was not fit for the job  He was a reasonable option given his prior leadership experience on missions