Arthur Miller uses The Crucible as a symbol for the Red Scare. In The Crucible, teenage girls accusedmany people in the town of Salem of being witches. Similarly, during the Red Scare hundreds of people were accused of being communist.
Almost everyone instantly believed these strong accusations because people were so frightened of witches and communists that they did not stop to consider the accusations they were making. The reason they were making these accusations was partly because of fear and additionally because by making these accusations they were put in a position of power and control. Abigail and other people accused of being witches and communist sometimes falsely agreed that they were just to escape being hung or put in prison and rejected by society.
The Crucible is a symbol of the Red Scare. They both include people falsely accusing others and doing so out of fear or the need for power, and the accused admitting to something that was not true just to avoid conflict.