In political jargon, useful idiot is a pejorative term used to describe people perceived as propagandists for a cause whose goals they do not understand, who are used cynically by the leaders of the cause.
The term was originally used to describe Soviet sympathizers in Western countries. The implication was that although the people in question naïvely thought of themselves as an ally of the Soviet Union, they were actually held in contempt and were being cynically used.
often being attributed to Lenin,
LENIN is supposed to have referred to blind defenders and apologists for the Soviet Union in the Western democracies as "useful idiots." Yet even Lenin might have been surprised at how far these useful idiots would carry their partisanship in later years -- including our own times.