[nicobn]

I don't mean to nitpick but your explanation is missing a critical detail. The chain of command for operational purposes (military operations) completely bypasses the Joints Chiefs of Staff and goes directly to the Unified Combatant Commands. By design, there is no military leader that has operational control over more than a fraction of US forces at a time, which further improves civilian control over the military.

The JCS have a very important role but their control is mostly administrative (doctrine, assignments, equipment, promotions, etc.).