Writer, some lefties say, is Tory (8)
I believe the answer is:
essayist
'writer' is the definition.
(I know that essayist is a type of writer)
'some lefties say is tory' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'ESSAYIST' is hidden within 'lefties say is tory'.
(Other definitions for essayist that I've seen before include "Writer of short literary pieces" , "Bacon maybe" , "Lamb, perhaps" , "Writer such as Addison" , "Writer of pieces on various subjects" .)