A new life awaits you, in the off-world colonies - the chance to begin again in a golden land of opportunity and adventure!
The guy from the past, who is familiar with 20th century dictators' methods, gets them to set up a program to brainwash the masses into emigration to Venus, and then they build fake spacecraft that don't go very far but the passengers don't return, and they send letters home saying everything is great (inspired by the Nazis sending fake letters from euthanasia victims).
The end is when he thinks he's on top of the world and essentially world dictator, but the people that he was advising politely force him onto one of the "spaceships" because his job "thinking outside the box" is finished and they have no more use for him.