Pressure from the past about to emerge, with views in opposition (9)
I believe the answer is:
polarised
'with views in opposition' is the definition.
(as in a polarised debate)
'pressure from the past about to emerge' is the wordplay.
'pressure' becomes 'p' (abbreviation).
'from the past' becomes 'old' (I've seen this in another clue).
'about' is an insertion indicator.
'to emerge' becomes 'arise' (I've seen this in another clue).
'old' enclosing 'arise' is 'olarised'.
'p'+'olarised'='POLARISED'
(Other definitions for polarised that I've seen before include "like some light" , "(Of light waves) vibrating in one plane" , "Extremely divided" , "Separate" , "in opposing camps" .)