### Clue: Flat-dweller in situ, moving among leaders in strategy (9)
### Answer: PLAINSMAN 
 ### Explanation: Definition: Flat-dweller
 [ IN + **the 1st lettes,respectively, of**(… leaders) "situ, moving among" ] **contained in**(in) PLAN(a strategy;a course of action).
Defn: A flatland dweller.