The movie Tail Gunner Joe, made in 1977, was a good presentation of how Joe McCarthy started.
In 1949, the Communists took over China sending the Nationalists to Formosa. The Russians, in violation of treaties, agreements, and principles of self determination, kept troops in the countries of Eastern Europe, East Germany, and East Berlin. The case of Alger Hiss caused many people to fear that Communists were in our government stealing secrets, scientific data, and passing on anything that might be valuable the Soviets. Korea became split between the North and South.
Many Americans became fearful that Communists might gradually take over our country. They did not want another Pearl Harbor to catch us off guard. No doubt there were some Communists in our government leftover from World War II. In the 30s many people experimented with Communism out of desperation. Our capitalist system had failed and people turned to something new. The vast majority of them realized that Communism was not the answer. Yet news of this brief association could ruin many lives.
Millions of lives had already been lost or ruined in United States and other nations in World War II. We had defeated the Nazis in Germany and the Fascists in Italy and Japan. Now we faced the evils of Communism in Europe and Asia. Our victory in WWII seemed almost futile. Fear, frustration, and suspicion were rampant. For a Nazi to become a Communist or a Communist to become a Nazi requires no real transformation. They are identical twins.
A mess like this made our country ripe for a demagogue. Senator Joseph McCarthy, a Republican from Wisconsin, stepped forward to fill the roll. McCarthy had won the 1946 Senate seat as part of the mid-term Congressional elections. In these off years, the party of the President, in this case Harry Truman, often looses seats in Congress. What the Republicans did in 1946 was really cool. The GOP won enough seats to become a Majority in both the House and Senate. This was the first time Republicans ruled since 1928. Republicans were priming themselves for the Presidential campaign in 1948. TBC