Guilt by Association

Guilt by association is a version of the ad hominem fallacy in which a person is said to be guilty of error because of the group he or she associates with.

Example:

Secretary of State Dean Acheson is soft on communism as you can see by the fuzzy-headed liberals who come to his White House cocktail parties and the bleeding hearts of his Democratic Party who call for "moderation and constraint" against Soviet terror.

Has any evidence been presented here that Acheson's actions are inappropriate in regards to communism? This sort of reasoning is an example of McCarthyism, the technique of smearing liberal Democrats that was so effectively used by the late Senator Joe McCarthy in the early 1950s. In fact, Acheson was strongly anti-communist and the architect of President Truman's firm policy of containing Soviet power.