JP 3-28, page 40

Chapter II II-6 JP 3-28 (3) Support provided under immediate response authority should be provided on an incremental, cost-reimbursable basis, where appropriate or legally required, but decisions to use DOD resources will not be delayed or denied based on the inability or unwillingness of the requester to make a commitment to reimburse DOD. DOD officials who authorize the expenditure of funds without first having satisfied all of the conditions necessary to properly exercise immediate response authority risk violating the Antideficiency Act, Title 31, USC, Section 1341. See Appendix F, “Reimbursement for Defense Support of Civil Authorities,” for additional guidance on reimbursement for DSCA. (4) State officials have the authority to direct state-level or local-level immediate response authority using NG personnel serving in state active duty or Title 32, USC, status if this is IAW the laws of that state. As not all state officials have immediate response authority, there may be delays in obtaining approval from the governor. (5) The distance from the incident to the DOD office or installation is not a limiting factor for the provision of support under immediate response authority. However, DOD officials should use the distance and the travel time to provide support as a factor in determining DOD’s ability to support the request for immediate response. (6) The scale of the event should also be a deciding factor for whether to provide support to incidents several miles or hundreds of miles away from the installation under immediate response authority. In some cases of a catastrophic incident, the demands for life-saving and life-sustaining capabilities may exceed both the state’s and USG’s ability to mobilize sufficient resources to meet the demand. In these circumstances, installations and facilities not directly impacted should be prepared to provide immediate response support if they are able to save lives, prevent human suffering, or prevent great property damage. For more information on immediate response authority, see DODD 3025.18, Defense Support of Civil Authorities (DSCA). b. Emergency Authority. Emergency authority is a federal military commander’s authority, in extraordinary emergency circumstances where prior authorization by the President is impossible and duly constituted local authorities are unable to control the situation, to engage temporarily in activities that are necessary to quell large-scale, unexpected civil disturbances because such activities are necessary to prevent significant loss of life or wanton destruction of property and are necessary to restore governmental function and public order or duly constituted federal, state, local, territorial, or tribal authorities are unable or decline to provide adequate protection for federal property or federal governmental functions. Responsible DOD officials and commanders will use all available means to seek presidential authorization through the chain of command while applying their emergency authority. Emergency authority should not be confused with immediate response authority. Federal forces acting under immediate response authority are still bound by the PCA and may not participate directly in law enforcement; whereas, emergency authority and actions taken under the Insurrection Act are exceptions to the PCA.