Member forced into a diplomatic mission (8)
I believe the answer is:
legation
'diplomatic mission' is the definition.
(legation is a kind of diplomatic mission)
'member forced into a' is the wordplay.
'member' becomes 'leg' (I've seen this before**).
'forced' is an anagram indicator.
'into'+'a'='intoa'
'intoa' is an anagram of 'ation'.
'leg'+'ation'='LEGATION'
(Other definitions for legation that I've seen before include "Official residence of diplomat and staff" , "A long tie (anag.)" , "Embassy" , "Diplomatic group or mission" , "Diplomatic minister and staff, and their residence" .)