Briefly made advances, then elected Communist (5)
I believe the answer is:
lenin
'communist' is the definition.
(Lenin is an example)
'briefly made advances then elected' is the wordplay.
'briefly made advances then' becomes 'len' (I can't justify this - if you can you should give a lot more credence to this answer).
'elected' becomes 'in'.
'len'+'in'='LENIN'
Can you help me to learn more?
(Other definitions for lenin that I've seen before include "Leader of the Russian Revolution" , "Revolutionary man" , "First Soviet leader" , "Head of the Communist state after the fall of the Tsar" , "Vladimir Ilyich -, Soviet premier" .)