The first Red Scare:
Before the stock market crash and the great depression that followed it, there was no right to strike and there was no collective bargaining.
"You don't like it, don't work here!"
This characterized business's attitude and at that time and they were supported by the courts and the police who looked upon striking laborers as criminals. Many workers and even wives and children died.
This served to legitimize abuse and exploitation making the pressure for change even more urgent. Business was resisting social change.
The moneyed and ruling classes were stunned by the Russian Revolution that deposed the Czar and set up a worker's state. Oppressed labor in the US began to look at the worker's state as an ideal.
Business's strategy was to associate striking labor with anarchists and communists.
It is often said that Roosevelt saved capitalism. If this is true, he did it by legitimizing collective bargaining and getting businesses to give concessions to labor.
The second Red Scare:
The Red Scare of the fifties was something else again. Part of it was an effort to use the fear and the stigma of communism to cultivate management friendly unions. This was also the time of the military industrial complex and there was pressure to replace the old enemies with new ones and international communism fill these requirements.
In the simplest terms,
The post World War I Red Scare was the reaction and the resistance to the demands for social change.
The Red Scare of the early fifties was to orient and unify the nation towards an international adversary.
I spent 30 minutes composing this piece only to discover that the thread is closed. Maybe it was the behavior of the member? The topic is perfectly good because we are often led to believe that both events are the same.