Urban populations started soaring because veterans were able to live in California. Rock n roll became a popular music genre because it promoted an African/white mix of music. Births started to soar because everyone was having children and the promotion of franchises began such as Mcd's and Denny's.
At the start of the Cold War both sides mobilized troops at the borders. America used fear and called this the Red Scare. When the Soviet Union finally created their own atomic bomb.
As time went on and the poverty levels in the Unite States started to go down, people started to leave the cities for the suburbs and minorities in the U.S. started to have a say in many of the problems in the U.S.