From Wikipedia:

Unique law

Normally, American federal law specifically charges the U.S. National Guard with dual federal and state missions. As the U.S. federal government abolished the jurisdiction of the state of Maryland and states rights in Washington, D.C. to establish a federal district, there is no elected governor to command this guard unit. This is the only national guard unit that reports only to the U.S. president.

The U.S. National Guard is the only United States military force empowered to function in a state or, in this case, a district status. Those functions range from limited actions during non-emergency situations to full scale law enforcement of martial law when local law enforcement officials can no longer maintain civil control. The National Guard may be called into federal service in response to a call by the President or Congress.

When the U.S. National Guard is called to federal service, the U.S. President serves as Commander-in-Chief. The federal mission assigned to the U.S. National Guard is: "To provide properly trained and equipped units for prompt mobilization for war, National emergency or as otherwise needed."

Trump Just Trumped The CIA and their rioters ...

He can order the troops to restore order without consequence, and delay of going through a state governor or any middleman.