One favouring state involvement went first (7)
I believe the answer is:
leftist
'one favouring state involvement' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'went first' is the wordplay.
'went' becomes 'left' (as in leaving).
'first' becomes 'ist' (ist resembles 1st).
'left'+'ist'='LEFTIST'
Can you help me to learn more?
(Other definitions for leftist that I've seen before include "Labour Party member" , "Labourite" , "Communist" , "Socialist supporter" , "Supporter of socialism" .)