https://www.veteranstoday.com/2020/04/18/trump-calls-up-secret-force-of-10000-us-army-possible-move-against-congress/

In an emergency, its duties are said to include evacuating government leaders from the capital, as well as “securing” the city and engaging in “homeland defense” against potential enemies both foreign and domestic, including protecting Washington, DC’s airspace and dealing with civil unrest. Its area of operations is said to include the District of Columbia and the surrounding areas in Maryland and Virginia.

I think this fits with open sky treaty expiration