African country's familiar populist politician changes sides (5)
I believe the answer is:
niger
'african country's' is the definition.
(Niger is an example)
I cannot understand how the remainder of the clue works.
(Other definitions for niger that I've seen before include "West African country, capital Niamey" , "West African republic" , "The black" , "African river flowing into the South Atlantic" , "W. African country" .)