Explore "Thin Edge" by Randall Garrett on Textopian. Read with annotations and highlights.
The Belt Cities could survive without the help of Earth, and the Supreme Congress of the United Nations of Earth knew it. But they also knew that "survive" did not by any means have the same semantic or factual content as "live comfortably". If Earth were to vanish overnight, the people of the Belt would live, but they would be seriously handicapped. On the other hand, the people of Earth could survive -- as they had for millennia -- without the Belt Cities, and while doing without Belt imports might be painful, it would by no means be deadly.
But both the Belt Cities and the Earth knew that the destruction of one would mean the collapse of the other as a civilization.