Political
The Lindbergh Law was passed that allowed the death penalty for certain interstate abductions. This law was created due to the abduction of Lindbergh's baby son by a gang. Police were also bribed to stay silent during the gang wars.
Social
Many gang wars erupted due to the big bucks the now illegal alcohol was worth. There was much violence and most of it was in Chicago. One famous massacre by Scarface was on Saint Valentines' Day. He was not convicted however.
Economic
After the 18th Amendment was passed people's bank savings began to increase and there were less absentees in industries. Merchants had to pay protection money to the gangs so they would not destroy their merchandise.