Former soldier welcomes current soldier back in Socialist Republic (7)
I believe the answer is:
vietnam
'socialist republic' is the definition.
(Vietnam is a socialist republic)
'former soldier welcomes current soldier back' is the wordplay.
'former soldier' becomes 'vet' (short for veteran).
'welcomes' means one lot of letters goes inside another (in sense of 'invites in').
'current' becomes 'i' (symbol for electric current).
'soldier' becomes 'man' (I've seen this before).
'back' says the letters should be written in reverse.
'man' written backwards gives 'nam'.
'vet' placed around 'i' is 'viet'.
'viet'+'nam'='VIETNAM'
'in' acts as a link.
(Other definitions for vietnam that I've seen before include "South-east Asia country" , "Country in Indochina" , "Asian country, capital Hanoi" , "Country at war with itself from the 1950s to 1970s" , "Far Eastern country" .)