On January 11, 2021, President Trump approved an Emergency Declaration for Washington D.C.
This article summaries the extensive authority such declarations give to the Executive branch of government.
Since January 11, many thousands of National Guard personnel have been assigned in D.C. Blockades at major roadways have been put in place. But who is in charge? As best I can tell, the authority of the Executive branch of government (Trump???) supersedes all others during a such declarations. This two minute video posted by a D.C. construction worker provides a feel for the extent of the security measures being taken.
What is going on in D.C.?