Final answer:
Joseph McCarthy used Alger Hiss as an example of communist corruption in the State Department, exploiting his case to support his accusations of widespread communist infiltration in the government.
Step-by-step explanation:
Joseph McCarthy used Alger Hiss as an example of communist corruption in the State Department. In 1948, Hiss was accused by a former Soviet spy of being a coconspirator and passing microfilmed documents to the Soviets. Although Hiss was not convicted of espionage, he was found guilty of perjury. McCarthy exploited this case to support his accusations of widespread communist infiltration in the government.