Bits of mischief with Left ousting Right to establish political platforms (6)
I believe the answer is:
planks
'political platforms' is the definition.
(plank can mean a political platform or policy)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for planks that I've seen before include "Pieces of wood" , "Boards" , "Stout lengths of sawn timber" .)