Explaining Deadly Force: The Foundational Elements


With millions of new self-defense customers, it’s becoming more important for dealers to impart the
circumstances when lethal force can be used. Using the foundational elements described here is a start.

Since the beginning of the pandemic, and concurrent with civil disturbances around the nation, we now have 10 million or more first-time gun owners. Most (if not all) bought their initial firearm for self-defense. But before those folks’ arrival, there were other gun owners who weren’t entirely clear exactly when the deadly force of a gun could legally be used to protect their own life, or the lives of other innocent parties.

These self-defense customers will have questions on this topic for experts like you. It’s been a long time since we’ve touched on those elements in this space. Let’s start with the foundation.

Foundational Elements

The firearm is a tool of deadly force (or lethal force, the terms are interchangeable). Deadly force is the degree of force which a reasonable, prudent person would consider likely to cause death or great bodily harm (i.e., crippling injury) if employed against another human being. 

Such force may only be used only in a situation of immediate, otherwise unavoidable danger of death or great bodily harm. Historically, this situation is created by the simultaneous presence of three criteria. Those criteria are most commonly known as Ability, Opportunity and Jeopardy.

The Ability Factor

The Ability factor means the opponent has the power to kill or cripple. This is at its most obvious when the opponent is armed with a deadly weapon: a gun, a knife or something that can be used as a bludgeon. But it can also be constituted by something known as disparity of force. In a disparity of force situation, the attacker(s) may be ostensibly unarmed, but within the totality of the circumstances are still likely to kill or cripple and don’t need a deadly weapon per se to do so.

Many things can constitute disparity of force. It exists if the opponent is much larger and/or much stronger than the defendant. It often takes the form of force of numbers: two or more assailants attacking a lone innocent person. Another element can be known or obviously recognizable high skill in unarmed combat: an opponent known to be a semi-pro boxer, for example, or a black belt in the martial arts. 

Male attacking female is often, but not always, disparity of force; the legal theory being the male of the species is generally larger and physically stronger and more culturally disposed to physical aggression than the female. Able-bodied people attacking the handicapped are certainly creating disparity of force. 

Position of disadvantage is an often-overlooked element of disparity of force element. The best-known recent case in which it was in play was George Zimmerman’s 2013 acquittal in the shooting death of Trayvon Martin, whom the evidence showed was beating Zimmerman’s head against the pavement when the latter fired the single, fatal shot in question.

The Opportunity Factor

The Opportunity factor means the opponent is capable of immediately employing his power to kill or to cripple. An attacker wielding a knife and shouting death threats from 100 yards away from his intended victim has Ability, but not yet Opportunity. At the same distance and armed with a rifle or even a handgun, the same attacker at the same distance would have both Ability and Opportunity.

With contact weapons — that is, a knife or club or even bare hands — physical obstacles between assailant and the intended victim of the attack will be another element of the Opportunity factor.

In 1983, Dennis Tueller of the Salt Lake City Police Department did the seminal testing that showed the average adult male could, from a standing start, close a gap of 7 yards and inflict a fatal knife wound in an average time of 1.5 seconds. 

Today, this may be the single most proven element of what is now known as force science, a term popularized by Professor Bill Lewinski. It has often been misinterpreted as a “21-foot rule,” implying it was justifiable to shoot a knife-wielder at a distance of 19′ but not from 23′. In fact, it’s simply a guideline as to how quickly a contact weapon may be employed, no more and no less. What the knife-wielder is doing at the moment is the key thing, which leads us to the final criterion.

Let’s face it: We live in an armed society where anyone carrying a gun or even a knife has Ability and Opportunity surrounding them as they walk.

The Jeopardy Factor

The Jeopardy factor is the element of “manifest intent.” In other words, intent to kill or cripple as manifested by the opponent’s words and/or actions. This is often the deciding factor. 

Let’s face it: We live in an armed society where anyone carrying a gun or even a knife has Ability and Opportunity surrounding them as they walk. They are no danger to anyone until they manifest an obvious criminal intent to harm an innocent person.

All these elements are seen through the lens of an ancient legacy of the English Common Law from which our own law derives: the Reasonable Man Doctrine. The judge can be expected to instruct the jury in any self-defense case, criminal or civil, to ask themselves, “What would a reasonable, prudent person have done in the same situation, knowing what the defendant knew?”

This is a three-pronged test. Prong One: What would the reasonable and prudent person — the logical, cautious individual — have done? Prong Two: In the exact same situation the facts and testimony in evidence show the defendant was facing, and not some fantasy woven by opposing counsel from whole cloth. Prong Three: Knowing what the defendant knew, not only in the seconds before the incident, but going all the way back to the time when that person decided to be armed. (State of mind is always critical in self-defense cases.) 

The belief one is in deadly danger warranting a lethal force response must be both reasonable and sincere.

Preclusion, Sincerity & Reasonableness

Ability, Opportunity and Jeopardy apply to what the attacker is doing, which triggers the armed-citizen’s response. Preclusion examines what the citizen could have done to avoid the situation. Could they reasonably expect to just walk away unharmed? If so, they should have done exactly that. Did the armed citizen do anything to provoke the situation or “keep the ball rolling” in an escalating situation? Was the citizen in a place where he or she had no right to be, or doing anything illegal at the time? Violating any of those precepts “shreds the mantle of innocence” and compromises a defense argument of self-protection.

The belief one is in deadly danger warranting a lethal-force response must be both reasonable and sincere. It’s reasonable to shoot a man threatening to kill you with a pistol, which turns out later to be a realistic toy … but only if the shooter reasonably believed it was a real gun. If I let you examine my realistic plastic toy copy of a Beretta 92, you can’t shoot me and claim the belief it was a real 9mm I was going to shoot you with. 

Conversely, as one prosecutor put it, someone might sincerely believe the person they shot was an alien about to abduct him to another planet, but it would not be a reasonable belief and therefore would not be forgiven by the court.

More To Come …

Above, we have the essential basics of what warrants the use of lethal force in defense of oneself or other innocent parties. 

However, some of your customers will have questions about issues such as retreat requirements and the Stand Your Ground principle, Castle Doctrine and other issues that in recent years have been the subjects of extremely twisted interpretation in the media and on the internet.

Click To Read More Shooting Industry January 2023 Issue Now!