The First and Second Red Scares were similar in many respects since they were both reactions to the rise of the Soviet Union in the wake of a world war and both involved government-sanctioned witch hunts for communists within the United States. However, one key difference in the federal government's response to these Scares is that, in general, it targeted different classes of people during each Scare in its attempts to counteract communism.
Anticommunist activities during the First Red Scare were more economic in nature, targeting organized labor organizations which were suspected of communist leanings. This makes sense because the First Red Scare occurred after a revolution in Russia toppled the tsar and established a new communist government. The federal government's aim in arresting suspected communists, such as during the Palmer Raids, was to prevent a similar revolution occurring in the United States.
During the Second Red Scare, the emphasis was less on preventing a mass uprising by the poor and more on counteracting Soviet espionage in the US government and influential industries, such as Hollywood. The House Un-American Activities Committee and Senator Joseph McCarthy's hearings frequently targeted people in the movie industry and government officials. This sort of anticommunist activity also makes sense for its time period since by then, the Russian Revolution was long in the past and the current political issue of the day was the Cold War, the ideological struggle between the USSR and the US after both became superpowers in the wake of WWII. There was more fear of a nuclear war than of a communist revolution.
During the Second Red Scare in the 1950s, the United States saw communism as more of an external threat and engaged in proxy wars around the world to contain its spread, while the United States of the 1920s was more isolationist.
