Final answer:
A commanding officer's endorsement must reflect the key principles related to their role in supporting the President as Commander in Chief, including the commitment to national defense and upholding the Constitution.
Step-by-step explanation:
A commanding officer's endorsement should reflect the principles outlined in various historical documents that define the role and responsibilities of the Commander in Chief, particularly as they relate to the defense of the nation and the execution of duties. The statements provided reference important notions such as the need for written opinions from principal officers on matters pertaining to their departments, an acknowledgment of the Commander in Chief's role in national defense, and the constitutional obligation of the President to preserve, protect, and defend the Constitution of the United States.
The endorsement must therefore include acknowledgment of these responsibilities and could possibly state the commitment of the commanding officer to support the President in their role as Commander in Chief, who has the power to lead the military and make critical decisions on national defense. Additionally, it may include affirmations of abiding by the Constitution and faithfully executing the duties of the office.