Use of Militia, National Guard, or Federal Armed Forces Within the District of Columbia Prior to 2020 [August 25, 2021] [open pdf - 2MB]
From the Introduction: "This report provides information on 10 instances in which the militia, National Guard, or federal armed forces were used for operations within the geographic boundaries of Washington, DC, due to violence or anticipated violence. Congress may find these cases helpful when considering the contemporary or future role of the National Guard and federal armed forces in the nation's capital."
CRS Report for Congress, R46886
Congressional Research Service: https://crsreports.congress.gov/