Argue with row about Labour's leader (7)
I believe the answer is:
wrangle
'argue' is the definition.
(I've seen this in another clue)
'with row about labour's leader' is the wordplay.
'with' becomes 'w' (short for with).
'row' becomes 'range' (range can mean a row or chain of things).
'about' means one lot of letters goes inside another.
'labour's leader' becomes 'l'.
'range' going around 'l' is 'rangle'.
'w'+'rangle'='WRANGLE'
(Other definitions for wrangle that I've seen before include "'Quarrel, brawl (7)'" , "Argue noisily" , "angry argument" , "Fight" , "noisy argument" .)