Flipping wrong to have left-winger ... (4)
I believe the answer is:
trot
'left-winger' is the definition.
(I've seen this before)
'flipping wrong' is the wordplay.
'flipping' says the letters should be written in reverse.
'wrong' becomes 'tort' (legal term).
'tort' back-to-front is 'TROT'.
'to have' is the link.
(Other definitions for trot that I've seen before include "Move at brisk pace" , "Communist - horse pace faster that a walk" , "(Horse's) moderate pace" , "Run (like a horse)" , "Left wing" .)