Party politician supports more or less (4)
I believe the answer is:
camp
'party' is the definition.
(both can mean a group of people)
'politician supports more or less' is the wordplay.
'politician' becomes 'amp' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'supports' is a charade indicator (letters next to each other) (bottom letters provide a support for the top ones).
'more or less' becomes 'c' (abbreviation for 'circa', meaning approximately).
'amp' put after 'c' is 'CAMP'.
Can you help me to learn more?
(Other definitions for camp that I've seen before include "party supporters" , "Coterie" , "Limp-wristed in tent?" , "Party adherents" , "Live in a tent" .)