Road to Republican state (4)
I believe the answer is:
aver
'state' is the definition.
(both can mean to declare)
'road to republican' is the wordplay.
'road' becomes 'ave' (abbreviation for avenue).
'to republican' becomes 'R' (abbreviation in US politics).
'ave'+'r'='AVER'
(Other definitions for aver that I've seen before include "protest" , "State decisively" , "Formally state" , "State firmly, propound" , "Vera could declare to be true" .)