Exhausted provincial politicians support employment (4,2)
I believe the answer is:
used up
'exhausted' is the definition.
('used-up' can be similar in meaning to 'exhausted')
'provincial politicians support employment' is the wordplay.
'provincial politicians' becomes 'dup' (Democratic Unionist Party of Northern Ireland).
'support' means one lot of letters go next to another.
'employment' becomes 'use' ('use' can be a synonym of 'employment').
'dup' after 'use' is 'USED-UP'.
(Other definitions for used up that I've seen before include "Consumed, finished" , "Spent" , "Exhausted the supply" , "Consumed completely" .)