Drunk Democrat leaves Republican tradesperson (9)
I believe the answer is:
plasterer
'tradesperson' is the definition.
(type of tradesperson)
I can't explain the rest of the clue.
(Other definitions for plasterer that I've seen before include "Workman who skims along" , "may get one drunk?" , "Artisan" , "Coverer of walls, ceilings, etc" , "Tradesman" .)