Caper results in country's leader being replaced (6)
I believe the answer is:
prance
'caper' is the definition.
(both can mean to skip or dance around)
I don't understand how the remainder of the clue works.
(Other definitions for prance that I've seen before include "Gambol" , "Leap or skip" , "Frolic" , "Caper, swagger" , "(Of horse) use high steps" .)