Republican employs stratagems (5)
I believe the answer is:
ruses
'stratagems' is the definition.
(I have seen 'Clever stratagems ' mean 'ruses' so perhaps 'stratagems' could also mean 'ruses')
'republican employs' is the wordplay.
'republican' becomes 'r' (abbreviation).
'employs' becomes 'uses' ('use' can be a synonym of 'employ').
'r'+'uses'='RUSES'
(Other definitions for ruses that I've seen before include "Cunning plans" , "cunning tricks" , "'Stratagems, tricks (5)'" , "Clever stratagems" , "Clever plans designed to deceive" .)