A Unified Combatant Command is a task organized command structure used to coordinate forces around one objective. Examples include CENTCOM (https://www.centcom.mil/), which coordinates the armed forces in the Middle East. My question is, is there anything like that to coordinate the forces responsible for D.C., including the Secret Service (https://www.secretservice.gov/), Capitol Police (https://www.uscp.gov/), Army/Air National Guard (https://dc.ng.mil/), etc.? (I'm really not sure how to shoehorn research into this, the whole reason I'm posting this is because I can't find much.)
Well, the President is Commander-in-Chief of the Armed Forces and there is also the Joint Chief of Staff. Given that the USA government is wary of concentrating all forces under one command - after all this is why the government has a tripartite structure with the legislative, executive and judicial branches; then it's only natural that there is a similar structure also in the military.