Emphasise policy must follow European articles (9)
I believe the answer is:
underline
'emphasise' is the definition.
(I know that emphasise can be written as underline)
'policy must follow european articles' is the wordplay.
'policy' becomes 'line' (I've seen this in another clue).
'must follow' means one lot of letters go next to another.
'european articles' becomes 'under' (as in part-of-speech. un+der).
'line' put after 'under' is 'UNDERLINE'.
(Other definitions for underline that I've seen before include "Emphasise, stress importance" , "Reinforce" , "Call attention to - highlight" , "Give extra weight to, stress" , "Emphasise with horizontal stroke of pen" .)