Who has the authority to prescribe force structure for each combatant command?

The correct answer is the President, as the President of the United States has the ultimate authority over the military and its strategy, including the force structure of combatant commands. The President is the Commander-in-Chief and thus possesses the constitutional power to dictate military policy and decisions, which encompasses the allocation and organization of forces across various combatant commands.

The President collaborates with the Department of Defense and the National Security Council to determine military readiness and resources. This enables effective responses to any threats or crises that arise, ensuring that each combatant command is equipped and structured to address its specific operational environment efficiently.

Although the Joint Chiefs of Staff and the Defense Secretary play critical roles in advising the President and implementing military strategy, the final authority rests with the President. Combatant Commanders, while responsible for executing military operations and managing resources in their respective areas, do not have the authority to prescribe the overarching force structure. Their focus is primarily on operational execution within the framework set by higher authorities.