Useful idiots.

In political jargon, the term 'useful idiot' was used to describe Soviet sympathizers in Western countries and the attitude of the Soviet government towards them. The implication was that though the person in question naïvely thought themselves an ally of the Soviets or other communists, they were actually held in contempt by them, and being cynically used.

The term is commonly attributed to Lenin, sometimes in the form 'useful idiots of the West'.

Wikipedia.