An artist must accept party runs microstate (7)
I believe the answer is:
andorra
'microstate' is the definition.
(I've seen this before)
'an artist must accept party runs' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'must accept' indicates putting letters inside.
'party' becomes 'do' (do is a kind of party).
'runs' becomes 'r' (cricket abbreviation).
'an'+'ra'='anra'
'do'+'r'='dor'
'anra' placed around 'dor' is 'ANDORRA'.
(Other definitions for andorra that I've seen before include "part of Europe" , "Radar on (anag) - European principality" , "Tiny European nation" , "Small republic in the eastern Pyrenees" , "mountainous country" .)