Final answer:
Senator Joseph McCarthy's anticommunist crusade initially targeted the U.S. State Department, claiming it was infiltrated by Communists. His tactics, characterized by baseless allegations, became known as McCarthyism, contributing to the Cold War era's Red Scare.
Step-by-step explanation:
Senator Joseph McCarthy's anticommunist crusade was first directed primarily against the U.S. State Department. McCarthy claimed there was a significant infiltration of Communists within the department, capitalizing on fears of the Cold War era. His actions evolved into a broader campaign of anti-Communist hysteria which came to be known as McCarthyism, a term that encompasses unfair tactics of accusing individuals of disloyalty without sufficient evidence.
In 1950, McCarthy's public accusations that the State Department harbored Communists captured the nation's attention and instigated a period of heightened fear and paranoia. These accusations relied on shaky evidence, fluctuating numbers of supposed Communists, and bold public claims that often lacked substantiation. Nevertheless, they influenced the political landscape and spurred on the Red Scare of the 1950s.
Throughout this period, McCarthy also targeted other government agencies and various sectors of society, but it was his initial focus on the State Department that marked the beginning of his infamous anticommunist crusade.