Does the president have full power to hire or fire military leaders at will? I've never considered that issue before. There have to be some limits, right? Maybe not.
10 USC §1161
§1161. Commissioned officers: limitations on dismissal
(a) No commissioned officer may be dismissed from any armed force except-(1) by sentence of a general court-martial;
(2) in commutation of a sentence of a general court-martial; or
(3) in time of war, by order of the President.