Insurrection Act of 1807.
[Determination that the various state and local authorities are not up to the task of responding to the growing unrest]
Call the ball.
INSURRECTION ACT: 10 USC Chapter 13 Insurrection
§251. Federal aid for State governments
§252. Use of militia and armed forces to enforce Federal authority.
§253. Interference with State and Federal law.
10 USC Ch. 15: MILITARY SUPPORT FOR CIVILIAN LAW ENFORCEMENT AGENCIES
War Powers Resolution can be found under 50 USC Chapter 33
National Disasters can be found under 50 USC Chapter 34