The entire story of AtlasShrugged can be seen as an answer to the question, what would happen if this sanction was revoked? When Atlas shrugs, relieving himself of the burden of carry the world, he is revoking his sanction.
The concept is apparently original in the thinking of AynRand and is foundational to her moral theory. She holds that evil is a parasite on the good and can only exist if the good tolerates it. To quote from /GaltsSpeech?: "Evil is impotent and has no power but that which we let it extort from us", and, "I saw that evil was impotent...and the only weapon of its triumph was the willingness of the good to serve it." Morality requires that we do not santion our own victimhood.
Throughout AtlasShrugged, numerous characters admit that there is something wrong with the world but they cannot put there finger on what it is. The concept they cannot grasp is the sanction of the victim. The first person to grasp the concept is /JohnGalt, who vows to stop the motor of the world by getting the creators of the world to withhold their sanction.
We first glimpse the concept in /SectioN121 when /HankRearden feels he is duty-bound to support his family, despite their hostility towards him.
In /SectioN146 the principle is stated explicitly by /DanConway: "I suppose somebody's got to be sacrificed. If it turned out to be me, I have no right to complain."