Tory ministers' debates (8)
I believe the answer is:
contends
'debates' is the definition.
('contend' can be a synonym of 'debate')
'tory ministers'' is the wordplay.
'tory' becomes 'con' (abbreviation for Conservative).
'ministers'' becomes 'tends' (I've seen this in another clue).
'con'+'tends'='CONTENDS'
(Other definitions for contends that I've seen before include "Strives against another" , "Vies" , "Maintains or asserts" , "Fights or argues" , "Strives; maintains" .)