The President has already thanked the National Guard, D.C. Police and Secret Service for doing a great job. Posted 45 minutes ago to Facebook.
Brian Cates reported on his Twitter a couple days back that SWAT teams from many federal agencies are being used to take up security duties so the troops can stand down.
As federal assets, these LEOs can be deployed anywhere, no matter what the local authorities say.
That seems to apply in particular to Mayor Bowser.