This article was originally published on May 29, 2020, and updated on June 2, 2020.

In the aftermath of the tragic killing of George Floyd by a Minneapolis police officer, riots and unrest have been spreading throughout the city of Minneapolis and the country. The Minnesota National Guard was activated by Governor Timothy Walz on May 28. As of June 1, no less than 23 states and the District of Columbia have activated their respective National Guard units. These National Guard members report to their respective governor and can actively take part in state law enforcement functions, which many of them are now doing.  The District of Columbia National Guard is an anomaly as it is not a state—it reports to the Secretary of Defense and President.

But now, President Donald Trump has involved himself as well.

Shortly after Governor Walz activated the Minnesota Guard on Thursday, Trump tweeted that he:

can’t stand back & watch this [the riots] happen to a great city, Minneapolis. A total lack of leadership. Either the Radical Left Mayor, Jacob Frey, get his act together and bring the city under control, or I will send in the National Guard and get the job done right.

Further, Trump tweeted that he “just spoke to Governor Walz and told him that the Military is with him all the way. Any difficulty and we will assume control but, when the looting starts the shooting starts … .”

On Monday, Trump again foreshadowed an intention to deploy the military domestically, stating that if governors were unable to end the violence, he would send in the military “to do the job for them.”  But at this time, no governor has requested federal military forces, nor has President Trump invoked the Insurrection Act, a key statute that authorizes the federal military to directly participate in law enforcement operations.

Nevertheless, five key legal issues have emerged associated with the President’s actions (outside of Trump’s showdown with Twitter, which placed a warning on the latter tweet, saying it glorified violence):

  1. Can the President use the military to respond to domestic unrest?
  2. What is the Insurrection Act and its substantive and procedural provisions?
  3. How does the military actually interpret its role in civil disturbance operations?
  4. What other legal authorities could potentially authorize a military role in domestic law enforcement operations?
  5. What are the military’s rules for the use of force in such a scenario—i.e. does looting justify shooting?

1. Can the President Use the Military to Respond to Domestic Unrest? 

Yes, but this is subject to certain, critical legal restrictions under the Posse Comitatus Act and the Insurrection Act.  The president is, of course, the commander-in-chief of the Armed Forces (and the D.C. National Guard), but he lacks the authority to use the military in any manner that he pleases. That authority is constrained by Congress and the courts and further informed by military instructions and doctrine.

Under the 1878 Posse Comitatus Act, Congress has limited the president’s ability to use the federal (title 10) military in domestic law enforcement operations such as searches, seizures, and arrests. A criminal statute, the Posse Comitatus Act makes it unlawful for the Army or Air Force to “execute the laws … except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.” So, as a general matter the president cannot simply call in federal military forces or nationalize state National Guard units to quell domestic civil disturbances in Minneapolis or elsewhere without pointing to a Posse Comitatus Act exception.

2. What are the Insurrection Act’s substantive and procedural provisions?

The Insurrection Act is, by far, the Posse Comitatus Act’s most important exception (although there are others, as discussed below). This is the legal key that unlocks the door to use federal military forces—whether through federalizing the National Guard or calling in “title 10 forces” (i.e. traditional federal military units) to quell civil unrest. Dating from 1807, there are four key Insurrection Act provisions (three substantive and one procedural) worth addressing.

First, a state legislature or governor could request assistance from the president under 10 U.S.C. § 251 “to suppress [an] Insurrection.” It states, in full:

If there is an insurrection in a State, the President, at the request of the State’s legislature, or Governor if the legislature cannot be convened, may call National Guards of other States into Federal service as well as use the Federal military to suppress the insurrection.

This authority was invoked in May 1992, when California Governor Pete Wilson turned to the Insurrection Act in requesting federal military assistance from President George H.W. Bush. This was in response to the Los Angeles riots, after a jury acquitted the officers involved in the arrest and beating of Rodney King. In requesting federal troops to patrol Los Angeles, Wilson specified that the California National Guard lacked the ability to quell the domestic disturbance. Shortly thereafter, Bush issued an executive order, which authorized the defense secretary to federalize the California National Guard and deploy active-duty Army and Marine personnel from bases in California to the scenes of the riots.

Will Minnesota or other state governors or legislatures seek federal military assistance? It appears unlikely at this time. The Minnesota legislature is controlled by the Democratic-Farmer-Labor (DFL) Party and Governor Walz is a member of the DFL. Besides their political differences, states have historically been reluctant to request this authority—Governor Kathleen Blanco requested that the Louisiana National Guard, under the control of Lt. Gen. Russell Honoré, remain under state authority in the aftermath of Hurricane Katrina. While now the unrest has spread to many states, no governor, as of June 2, has affirmatively indicated they will seek federal military assistance via the Insurrection Act.

But there are two Insurrection Act provisions that can be invoked by the president irrespective of a state’s request or underlying desires. Ironically, presidents have actually relied upon these provisions to uphold civil rights and protect the rights of minorities in the Deep South during the 1950s and 1960s.

Second, the Insurrection Act authorizes the President to deploy the military (federal or state) whenever he believes it necessary “to suppress an insurrection, domestic violence, unlawful combination or conspiracy.” The full body of this provision states:

Whenever the President considers that unlawful obstructions, combinations, or assemblages or rebellion against authority of United States makes it impracticable to enforce the law of the United States in any State or territory by judicial proceedings, the President may call into Federal service the militia of any State and use the Federal military to enforce the laws or suppress the rebellion.

Third, the president can use the armed forces when there is an interference with federal or state law. The most generalized provision, its precise scope also remains largely untested. The president may use the military to suppress insurrection, domestic violence, unlawful combination or conspiracy if:

(a) it so hinders the execution of law of that State and of the United States and it deprives citizens of constitutional rights (e.g. due process); or (b) it opposes or obstructs the execution of laws or impedes the course of justice. In the event of the deprivation of rights, the State is deemed to have denied its citizens equal protection of laws.

Finally, prior to invoking the Insurrection Act, the president, with the assistance of the attorney general, must first issue a “proclamation to disperse.” This mandatory procedure requires that:

Whenever the President considers it necessary to use the militia or the armed forces under this chapter, he shall, by proclamation, immediately order the insurgents to disperse and retire peaceably to their abodes within a limited time.

If the situation is not resolved and dispersal does not occur, the President may issue an executive order and send in the military. Such dispersal proclamations are normally quite short but remain an important procedural requirement that is part of the Insurrection Act statutory scheme.  In 1968, President Lyndon Johnson issued a dispersal order that “commanded all persons engaged in acts of violence threatening the Washington Metropolitan Area and obstructing the execution of the laws to cease and desist therefrom and to disperse forthwith.”

The Insurrection Act was invoked in the 1950s and 1960s, when presidents used it to enforce civil rights laws and end segregation in the South. Presidents Dwight Eisenhower and John Kennedy used the Act in Arkansas, Alabama, and Mississippi to enforce civil rights laws. Kennedy invoked the interference with federal law provision to send federal military troops to Birmingham, Alabama during the civil rights protests.

In modern times, the decision to federalize the state National Guard is made carefully, after close consultation with the Governor of the respective state. Governor Blanco of Louisiana specifically did not request that President George W. Bush invoke the Insurrection Act. In contrast, Governor Wilson of California requested support from President George H.W. Bush to assist with restoring law and order in Los Angeles.

In sum, invoking the Insurrection Act remains a rare occurrence in U.S. history, used in the most extraordinary circumstances, such as the complete disregard for enforcing federal civil rights laws or massive unrest in the nation’s second largest city. Despite the Insurrection Act’s invocation in Los Angeles, it has not been used in 28 years. And it was not invoked in Ferguson, Missouri. Nor was it invoked in Baltimore, Maryland during the riots that occurred in the aftermath of the death of Freddie Gray, who was killed by police officers in 2015. Nor was it invoked in the aftermath of Hurricane Katrina. Finally, it remains unclear whether the invocation of these two provisions are subject to judicial review. Courts have historically been reluctant to wade into these complex federalism and separation of powers waters and will certainly be wary of providing specific guidance.

3. How does the military actually interpret its role in civil disturbance operations?

Critically, if the Insurrection Act is ultimately invoked, the Department of Defense still interprets its role as one that supports the civilian law enforcement agencies. This is reiterated in the military instruction addressing Insurrection Act implementation, titled “Defense Support of Civilian Law Enforcement Agencies.” To be sure, the military would be under federal (not state or local) command and control, but the military interprets it authority as one that supports and does not supplant the civilian law enforcement effort. According to the military instruction:

Any employment of Federal military forces in support of law enforcement operations shall maintain the primacy of civilian authority and unless otherwise directed by the President, responsibility for the management of the Federal response to civil disturbances rests with the Attorney General (emphasis added).

There is little case law governing the military’s precise role in so-called “civil disturbance operations.” But past and existing guidance supports the DoD’s interpretation of how the Insurrection Act would be implemented.  For example, an Attorney General opinion dated right before the Civil War stated that “[under the Insurrection Act] the President may employ the militia and the land and naval forces for the purpose of causing the laws to be executed; but when a military force is called into the field for that purpose, its operations must be purely defensive, and the military power on such occasion must be kept in strict subordination to the civil authority.”  This is reaffirmed in federal regulation, which also states that any employment of federal military forces in support of law enforcement operations shall maintain the primacy of civil authority.

4. What other legal authorities could potentially authorize a military role in law domestic law enforcement operations?

Independent of the all-important Insurrection Act and its implementing instructions, there are three other avenues for the military to provide direct assistance to law enforcement activities.

First, martial law occurs when the military actually takes the lead and assumes control until civil authority can be restored. That has not (yet) been discussed and is rarely invoked in modern times. The last time a president declared martial law, he did so pursuant to an express congressional authorization in Hawaii (a U.S. territory) during World War II. The most recent state or local martial law declaration occurred in 1966, when the California governor imposed martial law to suppress civil unrest in San Francisco following the shooting of a black teenager by a white police officer.

Second, there is an “extraordinary emergency authority” when the military can enforce the law “where prior authorization of the President is impossible and duly constituted authorities are unable to control the situation.”  This authority, also in regulation, is limited to activities necessary to quell large-scale unexpected civil disturbances to prevent a significant loss of life or wanton destruction of property and are necessary to restore governmental function.

Third, the Posse Comitatus Act makes clear that its prohibitions do not apply in cases or circumstances expressly authorized by an Act of Congress.  The DoD instruction lists at least 14 such statues independent of the Insurrection Act that could be used, but there are likely more.  Some are fairly obscure, but others are not. For example, 18 U.S.C. § 1751 authorizes protection of the President, Vice President, and other designated dignitaries.

5. Military Rules and the Use of Force: Does Looting Justify Shooting? 

No. Federal military forces responding to civil unrest comply with Standing Rules for the use of Force (SRUF). These rules are generally less permissive than Standing Rules of Engagement (SROE) that the military uses in operational environments overseas and more traditional military missions. Both sets of rules are promulgated via the chairman of the Joint Chiefs of Staff and tailored to the individual mission. To be sure, these rules governing the use of force are policy guidance, but they reflect the complex strategic, legal, and morality issues that are in play whenever the U.S. military uses force on our own soil.

While the rules of force for a military domestic operation will be tailored to the unique mission in coordination with the state law enforcement agency and governing state law, certain core principles remain constant. For example, force is to be used only as a last resort, and the force used should be the minimum necessary. Further, deadly force is to be used only when all lesser means have failed or cannot be reasonably employed.

Of course, the rules for the use of force do not limit the inherent right of self-defense of people. It also authorizes force—including deadly force—to protect three specified assets: (1) assets vital to national security (such as nuclear command and control facilities); (2) inherently dangerous property (such as missiles, rockets, and explosives); and (3) national critical infrastructure (such as designated public utilities). None of these appear to apply in Minnesota or at other current sites of unrest, which tend to be clustered in cities far from sensitive military facilities, weapons depots and critical infrastructure.

Using deadly force aggressively to stop looting clearly violates the governing rules for the use of force, principles of de-escalation, and the principles of using only minimum force, as a last resort.

The unrest following the death of George Floyd is a rapidly developing situation. Answering these five questions are especially important as the violence has increased in recent days.

The views expressed here are the author’s personal views and do not necessarily reflect those of the Department of Defense, the United States Navy, or any other department or agency of the United States Government.

Image: Members of the National Guard join police in holding a line on the fourth day of protests on May 29, 2020 in Minneapolis, Minnesota. Photo by Scott Olson/Getty Images