As of now there are only two requirements to be President of the United States; You must be 35 years old, and must be a natural born citizen.
These requirements need to be amended to reflect that to be President of the United States of America, Commander-in-Chief of the Armed Forces you must serve a minimum of 4 years of active duty status in the military. This will not require a particular branch of military service or be subjected to rank obtained upon leaving military service. However, status upon discharge will be crucial i.e. the service member must be honorably discharged to be eligible to run for President. The commander of the military should be in it before they can lead it.