Rates a Republican wearing spats (7)
I believe the answer is:
tariffs
'rates' is the definition.
(I know this)
'a republican wearing spats' is the wordplay.
'republican' becomes 'r' (abbreviation).
'wearing' is an insertion indicator.
'spats' becomes 'tiffs' ('tiff' can be a synonym of 'spat').
'a'+'r'='ar'
'ar' put inside 'tiffs' is 'TARIFFS'.
(Other definitions for tariffs that I've seen before include "taxes" , "List of customs duties or charges" , "Lists of charges" .)