Error in party politics (4)
I believe the answer is:
typo
'error' is the definition.
(typographical error)
'in party politics' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TYPO' can be found hidden inside 'party politics'.
(Other definitions for typo that I've seen before include "Keyboard slip-up" , "Finger problem" , "Literal - printing mistake" , "Printing error (colloq.)" , "Small printing error" .)