“Useful idiot”: Someone who propagandises for a cause without fully comprehending the cause’s goals and who is cynically used by the cause’s leaders.
The phrase has been credited to Vladimir Lenin – but there’s no proof he actually came up with it – and gained ground during the Cold War when it was used to describe non-Communists who willingly and unthinkingly spread Communist propaganda.
Replace “Communist propaganda” with “ Putin’s agenda ” and you’ll fast see we’re up to our knees in them in the West today.