McCarthyism

from WordNet (r) 3.0 (2006)

McCarthyism
    n 1: unscrupulously accusing people of disloyalty (as by saying
         they were Communists)

from The Collaborative International Dictionary of English v.0.48

McCarthyism \McCarthyism\ prop. n. [from Senator Joseph
   McCarthy, who repeatedly asserted without evidence that
   numerous communists were present in the United States
   government.]
   Unscrupulously accusing people of disloyalty (as by saying
   they were Communists).
   [WordNet 1.5 +PJC]