A Republican gets into outsize rows (4)
I believe the answer is:
oars
'rows' is the definition.
(I've seen this before)
'a republican gets into outsize' is the wordplay.
'republican' becomes 'r' (abbreviation).
'gets into' indicates putting letters inside.
'outsize' becomes 'os'.
'a'+'r'='ar'
'ar' placed within 'os' is 'OARS'.
(Other definitions for oars that I've seen before include "Propelling implements" , "Soar around the rowers" , "Henley sportsmen" , "Manually operated boat propellers" , "Boating implements" .)