The President doesn't just decide who to kill, though. He relies on advisers, and delegates a lot to commanders in the field. Power is distributed throughout the chain of command, in both the afferent and efferent directions: higher-ups live in a world of information almost entirely constructed by what lower-downs tell them, and in turn must rely on the competence of individual contributors to implement policy.

For that matter, a lot of management responsibility amounts to letting people do their thing, then backing them up when they encounter trouble.