Conservative failure getting nearer (6)
I believe the answer is:
closer
'nearer' is the definition.
('close' can be a synonym of 'near')
'conservative failure getting' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'failure' becomes 'loser' (someone who has failed).
'getting' is a charade indicator (letters next to each other).
'c'+'loser'='CLOSER'
(Other definitions for closer that I've seen before include "One who is skilled at bringing a business transaction to a satisfactory conclusion" , "one concludes" , "Comparatively near" , "More airless; nearer" , "more reticent" .)