I read that the National Guard is under state control unless mobilized for a federal event (such as this), then they are under the feds.
If they fall under the fed, I assume the President can delegate this to whomever he chooses.
Who knows about the National Guard chain of command? Anyone?
DC is not a State. The DC National Guard is authorized by Congress and commanded (at the moment) by President Barack Hussein Obama.
If they are going to stop Trump, the DC Guard is the tip of the spear.