The commonality between the Indus, Huang and Nile Valley civilizations is the fact that all began in fertile river valleys.
The Vietnam War severely damaged the U.S. economy. Unwilling to raise taxes to pay for the war, President Johnson unleashed a cycle of inflation. The war also weakened U.S. military morale and undermined, for a time, the U.S. commitment to internationalism.
Well it was around the Cotton Revolution so think about it... Cotton... ;)
