The correct answer to this open question is the following.
When senator Joseph McCarthy decided to run for a second term, the issue that became the focus of his reelection campaign was anticommunism. Joseph McCarthy was a Republican Senator for the state of Wisconsin that started the Red Scare, accusing many members of the military and the federal US government of having ties with Communists. He damaged the reputation of many people because he accused but never showed any serious prove at all. After the televised hearings known as "Army-McCarthy," he lost all of his credibility and his political career abruptly ended.