Provincial politicians to admit fighting over draft (4,2)
I believe the answer is:
draw up
'draft' is the definition.
(I've seen this in another clue)
'provincial politicians to admit fighting over' is the wordplay.
'provincial politicians' becomes 'DUP' (Democratic Unionist Party of Northern Ireland).
'to admit' indicates putting letters inside.
'fighting' becomes 'war'.
'over' shows that the letters should be reversed in order.
'war' reversed gives 'raw'.
'dup' enclosing 'raw' is 'DRAW UP'.
(Other definitions for draw up that I've seen before include "Draft" , "table" , "Compose" , "Prepare (document)" .)