Socialist delivered in the act (3-6)
I believe the answer is:
red-handed
'in the act' is the definition.
(I've seen this before)
'socialist delivered' is the wordplay.
'socialist' becomes 'red' (socialism is often associated with the colour red).
'delivered' becomes 'handed' (I can't explain this - if you can you should believe this answer much more).
'red'+'handed'='RED-HANDED'
Can you help me to learn more?
(Other definitions for red-handed that I've seen before include "Catch someone thus in the act" , "In the act of crime - may be caught thus" , "Caught ... ......, apprehended in the act of crime" , "Colourfully caught in the act" , "(Caught) in the act of committing a crime" .)