What events during the late 1940s caused Americans to worry about internal society?

Answer 1

The communist threat made clear by the Soviet Union and their increasing role as a world power led to internal fears of communism and the 'red scare'.

Answer 2

Women had "tasted" the male workforce. They had just proven, during the war, that they were completely capable of filling a man's shoes. This had/has emmense ramifications. In the U.S. children start to be "handed over" ( more in the 50's) to caregivers. While at the same time, the renewed prosperity provided an opportunity for parents who had eeked out the Great Depression as youngsters themselves, to lavish the offspring with what they had gone without, and then some.
Employing the returning vets was paramount, of course. It became a "jammed funnel", as too many applicants for too few opportunities poured into the civilian workforce.
Internationally, the Soviet Union tightened its noose in Germany and Northern Europe. To make it most worrisome, they had soon obtained the technology for the atomic bomb as well. The Cold War was on. Over time, a new fear from within developed as Americans contimplated how many Communist sympithizers there were and what organizations were infiltrated and to what extent? A palpable tension developed between Business and Government interests and those of a burgeoning Labor movement. Labor continued to organize, business mounted resistance on many fronts, and within the mix dwelled the fear in all aspects of society, of the infiltration of Communism into the frey.

Answer 3

By the late 1940s, and early 1950s, Americans not only worried about demons such as the "Red Scare", but also "The Assassin of Youth" (Cannabis Sativa or Marijuana), and then - you'll love this one - comic books!!