Curt treatment of Republican wearing mini dress (5,6)
I believe the answer is:
short shrift
'curt treatment' is the definition.
(I've seen this before)
'republican wearing mini dress' is the wordplay.
'republican' becomes 'r' (abbreviation).
'wearing' means one lot of letters goes inside another.
'mini' becomes 'short' ('short' can be similar in meaning to 'mini').
'dress' becomes 'shift' (shift is a kind of dress**).
'short'+'shift'='shortshift'
'r' placed within 'shortshift' is 'SHORT SHRIFT'.
'of' is the link.
(Other definitions for short shrift that I've seen before include "Summary treatment of a matter" , "Brief and unsympathetic treatment" , "Curt treatment" .)