Marxist leaders in Ethiopia ensured Mengistu free from blame (6)
I believe the answer is:
redeem
'free from blame' is the definition.
'redeem' can be an answer for 'free' (I've seen this before). I'm unsure of the 'from blame' bit.
'marxist leaders in ethiopia ensured mengistu' is the wordplay.
'marxist' becomes 'red' (red can mean a leftwing person).
'leaders in' suggests taking the first letters.
The initial letters of 'ethiopia ensured mengistu' is 'eem'.
'red'+'eem'='REDEEM'
Can you help me to learn more?
(Other definitions for redeem that I've seen before include "Make good" , "Repay (a bond); save" , "Save, perhaps from pawn" , "Recover by means of a payment" , "Save or cash in" .)