A Republican tucked into drink — porter, perhaps (6)
I believe the answer is:
bearer
'porter perhaps' is the definition.
(someone bearing or porting things)
'a republican tucked into drink' is the wordplay.
'republican' becomes 'r' (abbreviation).
'tucked into' indicates putting letters inside.
'drink' becomes 'beer' (beer is a kind of drink).
'a'+'r'='ar'
'ar' going inside 'beer' is 'BEARER'.
(Other definitions for bearer that I've seen before include "He presents bill" , "He helps to carry something - sometimes a coffin" , "Person carrying" , "agent" , "One who carries, maybe a coffin" .)