useful idiot

Meanings

1. A Communist sympathizer in Western countries, from the perspective of the political right.
2. One who unwittingly supports a malignant cause through naive attempts to be a force for good.

Etymology

The earliest known usage in Western media is in a 1948 article in the social-democratic Italian paper L'Umanità – as cited in the New York Times article on Italian politics (see quotations). Often misattributed to Vladimir Lenin.