Outlaw and card-carrying lecturer cause most support (9)
I believe the answer is:
bandwagon
'cause most support' is the definition.
'bandwagon' can be an answer for 'cause' (I have seen 'fashionable cause' mean 'bandwagon' so perhaps 'cause' could also mean 'bandwagon'). I'm not certain of the 'most support' bit.
'outlaw and card-carrying lecturer' is the wordplay.
'outlaw' becomes 'ban' (banning is a kind of outlawing).
'and' says to put letters next to each other.
'card' becomes 'wag' (both can mean a humorous person).
'carrying' is an insertion indicator.
'lecturer' becomes 'don' (don can mean an academic).
'wag' inserted within 'don' is 'dwagon'.
'ban'+'dwagon'='BANDWAGON'
Can you help me to learn more?
(Other definitions for bandwagon that I've seen before include "Suddenly fashionable cause or activity" , "latest trend" , "See 24" , "vehicle for musicians" , "Fashionable movement" .)