Commie thus ahead of those marked for surveillance in America? (9)
I believe the answer is:
socialist
'commie' is the definition.
(communist)
'thus ahead of those marked for surveillance in america?' is the wordplay.
I cannot quite see how this works, but
'thus' could be 'so' (synonyms) and 'so' is located in the answer.
'america?' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is found within the answer.
This explanation may well be incorrect...
(Other definitions for socialist that I've seen before include "Left-winger" , "Fabian" , "Lefty" , "Politician of the left" , "One's left" .)