What are the preconditions of use of force?

Answer 1

Inherent right self defense

Defense of others

Vital national security

Inherently dangerous property

Critical infrastructure

Serious offense against others

Prisoner escape

Arrest or apprehension

Answer 2

According to AFI 31-207, the document that guides use of force by military personnel, there are 7 preconditions to deadly force. They are as follows (largely copied from the source with minor clarifications). First, however, the concept of objective reasonableness is discussed- to paraphrase, objective reasonableness is whether any reasonable individual in the officer's position would (reasonably) have made the same or similar action. This is largely based on the officer's individual perception of risk.

The use of deadly force must meet the "objective reasonableness" standard. Deadly force, when reasonable, should be used only when all lesser means of force have failed or cannot reasonably be employed. It must be noted that when deadly force is used, the officer/sentry must be able to articulate objective reasonableness based on his/her perception of the threat and the totality of the circumstances. Deadly force is authorized under the following circumstances as set forth in CJCSI 3121.01B, Enclosure L.

1. Inherent Right of Self-Defense. Applies when an individual reasonably believes he/she is in imminent danger of death or serious bodily harm. Deadly force is authorized when individuals reasonably believe that a person poses an imminent threat of death or serious bodily harm to DoD forces. Unit self defense includes the defense of other DoD forces in the vicinity.

Paraphrase: Any officer of the peace has at all times a right, or possibly even a moral obligation, to save his own life, or the lives of those he works with. If this requires deadly force, then so be it, but it should be noted from the context of the document that deadly force is always a last resort.

2. Defense of Others. When an officer/sentry reasonably believes others are in imminent danger of death or serious bodily harm. Deadly force is authorized in defense of non-DoD persons in the vicinity, when directly related to the assigned mission.

Paraphrase: For example, if one has sufficient evidence to believe that a suspect will kill or injure others, as an active shooter in a school setting, deadly force is authorized to stop the person from committing that offense.

3. Assets Vital to National Security. Deadly force is authorized when deadly force
reasonably appears to be necessary to prevent the actual theft or sabotage of assets vital to national security. The DoD designates its assets as "vital to national security" only when their loss, damage, or compromise would seriously jeopardize the fulfillment of a national defense mission. Installation commanders must identify these resources specifically designated as assets vital to national security, and the procedures they will use to inform armed personnel of such specifically designated property in their installation security instruction.

Paraphrase: This applies largely to the high-tech stuff that the US controls- spy planes, fighter jets, nuclear weapons, etc. Also certain important computer systems.

4. Inherently Dangerous Property. Deadly force is authorized when it reasonably appears to be necessary to prevent the actual theft or sabotage of inherently dangerous property. Property is considered inherently dangerous if its theft or sabotage would present a substantial danger of death or serious bodily harm to others. This includes weapons, ammunition, missiles, rockets, explosives, chemical agents, and special nuclear material. Installation commanders must identify
resources specifically designated as inherently dangerous to others and procedures they will use to inform armed personnel of such specifically designated property in their installation security instruction.

Paraphrase: For example, if a suspect appears to be attempting to steal or sabotage weaponized anthrax, lethal force is authorized to stop him from doing so. Personal firearms also fall into this category- but remember, it has to be objectively reasonable. Knowing that someone has a gun is not a good reason to shoot him- seeing him going for it is.

5. National Critical Infrastructure. Deadly force is authorized when deadly force
reasonably appears to be necessary to prevent the sabotage of national critical infrastructure. This includes the destruction of public utilities or similar critical infrastructure vital to public health or safety, the damage of which would create an imminent danger of death or serious bodily harm.

Paraphrase: Water treatment plants, energy stations, etc., buildings or equipment which could reasonably cause death if they were disabled or destroyed (if the power goes out in the winter, for instance, elderly people could freeze to death).

6. Serious Offenses Against Persons. Deadly force is authorized when deadly force
reasonably appears to be necessary to prevent the commission of a serious offense that involves imminent threat of death or serious bodily harm (for example, setting fire to an inhabited dwelling or encountering a sniper), including the defense of other persons, where deadly force is directed against the person threatening to commit the offense. Examples include murder, armed robbery and aggravated assault.

Paraphrase: Basically, if an individual is threatening to commit a serious crime, and has a reasonable ability to commit said crime, lethal force is authorized.

7. Escape. Deadly force is authorized when it reasonably appears to be necessary to prevent the escape of a prisoner, provided there is probable cause to believe such person(s) have committed or attempted to commit a serious offense, that is, one that involves imminent threat of death or serious bodily harm, and would pose an imminent threat of death or serious bodily harm to DoD forces or others in the vicinity.

Paraphrase: For similar reasons to 6, if a prisoner escapes, and shows a reasonable intent to harm innocent victims, lethal force is authorized in the attempt to recapture.

8. Arrest or Apprehension. Deadly force is authorized when deadly force reasonably
appears necessary to arrest or apprehend a person who, there is probable cause to believe, has committed a serious offense (as indicated in paragraphs 1, 2, 3, 4, 5, 6, and 7).

Paraphrase: If the suspect is believed to have committed a serious, violent offense, lethal force is authorized in the attempt to capture the individual.

There you have it- 7 preconditions and one inalienable right. Those are the instances lethal force is authorized. Serious offenses are almost universally violent crimes- possession of drugs, even with intent to sell, is not enough to warrant the use of deadly force on a fleeing suspect. That what tasers are for.