The name of the drill comes from Dennis Tueller who, in a 1983 SWAT Magazine article, sought to determine when a potential attacker armed with a contact weapon would be inside a police officer's danger zone: that is, too close for the officer to have sufficient time to draw his weapon and shoot a suspect before the suspect was close enough to use his or her contact weapon. Tueller explained:
Consider this. How long does it take for you to draw your handgun and place two center hits on a man-size target at seven yards? Those of us who have learned and practiced proper pistolcraft techniques would say that a time of about one and one-half seconds is acceptable for that drill.
With that in mind, let's consider what might be called the "Danger Zone" if you are confronted by an adversary armed with an edged or blunt weapon. At what distance does this adversary enter your Danger Zone and become a lethal threat to you?
We have done some testing along those lines recently and have found that an average healthy adult male [from a standing static position] can cover the traditional seven yard distance in a time of (you guessed it) about one and one-half seconds. It would be safe to say then that an armed attacker at 21 feet is well within your Danger Zone.So what is the relevance of this to self-defense? Well, Teuller's observations were taken by trainers and, according to Richard Mann, developed into "a tactical axiom: If an armed individual was within 21 feet of you, you would be justified in shooting to defend yourself." Mann also notes that "[a]ccording to Dave Starin, retired SWAT officer and former director of training at Gunsite Academy, 'It changed many agencies use-of-force policies and training programs and has also been used for decades in use-of-force reviews and court cases.'" The problem, which we will discuss farther below, is that:
Some trainers would teach their students they were unjustified shooting an edge-weapon-armed attacker farther than 21 feet away. Others would preach the opposite and equally stupid idea that one was always justified shooting the same imaginary attacker within 21 feet regardless of any other factors. The reality, of course, is much more complicated. All instances of lethal force must be justified with the totality of the circumstances.(See also, "Edged Weapon Defense: Is the 21-foot Rule Valid? Part 1", USAdojo.com; "Re-Engineering Training On Police Use Of Force," (PDF) pp. 14-15).
So, how does this work in use-of-force reviews and court cases? In a very good article from Andrew Branca, Branca discusses this and a lot more in the context of Michael Drejka's case. Basically, though, self-defense comes down to the issue of whether a defender reasonably believed that an aggressor presents imminent threat of death or grave bodily harm when defensive force is applied. Three factors are generally considered: ability, opportunity, and jeopardy (AOJ). “Ability” has to do with whether the threat have the ability to cause harm. “Jeopardy” (aka, “intent”) considers whether the aggressor is conducting himself in such a manner that one can infer an intent to cause the defender harm. "Opportunity" "refers to the issue of whether an apparent threat who has both the 'ability' to cause harm to the defender and the apparent intent to place the defender in 'jeopardy, also has the 'opportunity' to do so."
With firearms, Branca explains, "opportunity" is generally not an issue because of the nature of the weapon: if the aggressor can see you, he or she can probably shoot you. It plays more of a role in contact weapons. "In that case," writes Branca, "it is necessary for the attacker to get close enough to the victim in order to have the 'opportunity' to harm the victim with that weapon." Branca continues:
Obviously, then, it is of critical importance to understand at what distance an attacker armed with an impact weapon has come close enough to constitute an imminent threat. In particular, an attacker further than that distance would not yet constitute an imminent threat, and the use of defensive force against such a too-distant attacker would not yet be legally justified.Thus, the 21-foot rule can become a useful tool for determining when an attacker is close enough to constitute an imminent threat. Or, as Branca puts it: "The distance at which that impact weapon bearing attacker becomes an imminent threat, then, is whatever distance that attacker can cross in that 1.5 seconds (or less). Once inside that distance, the attacker can strike the defender with their weapon before the defender can thwart the attack." (Italics on original). Or, in other words, "[a]ssuming that 'ability' and 'jeopardy are also present, at that distance of 21 feet that attacker has, therefore, become an imminent threat against which defensive force is justifiable."
Branca continues his analysis by examining why the 21-foot rule was an impediment to the prosecutor in Drejka's case and how the prosecutor's use-of-force expert dishonestly presented testimony that the 21-foot rule only applied to cutting weapons and not contact weapons in general. But while the rest of Branca's analysis is useful in illustrating that prosecutors are no better than ambulance chasers in making their case, the idea that the 21-foot rule establishes some bright line between when force is justified and when it is not is false.
First of all, Tueller did not say that once an aggressor is less than 21-feet away that he/she is within an officer's danger zone. Rather, he stated: "It would be safe to say then that an armed attacker at 21 feet is well within your Danger Zone." (Underline added).The 21-foot rule was simply a method of describing a point in time when an attacker could strike as fast or faster than an officer could respond. It was not a hard and fast rule--nor was it intended to be--of when an aggressor posed an imminent threat.
Von Kliem recently noted in an article at Police One that "Force Science studies ... have documented the ability of subjects to sprint and perform a slash in 1.5 seconds from distances closer to 30 feet!" In addition, as Bob Irwin observes,"[r]esearch by Dr. Bill Lewinski of The Force Science Research Center and Dr. Marvin Fackler has repeatedly shown that officer reaction times are significantly longer than commonly believed." He adds:
The Force Science Research Center has shown that it takes the average officer about half a second to perceive a threat and approximately another half second to decide what to do about it. All of this has to happen before the officer begins his or her draw stroke. What this means is that with the threat closing at seven feet per half second, we are closer to a 35-foot rule.Returning to Kliem's article, he continues by discussing the case of Buchanan v. City of San Jose, where the court noted that the just because a threat presented itself beyond 21-feet does not mean that it was not an imminent threat. The relevant facts of that case, as Kliem describes them, are:
And it is extremely difficult to smoothly draw and accurately fire when under a life-threatening attack. So that means that we had better add another 10 feet to allow for the attacker to keep coming if we miss center mass or even if we hit him, even mortally wound him, and he doesn't go down.
It's now the 45-foot rule.
Officers responded to an emergency call that a man was threatening a family with a knife. Sadly, it turned out the man had called the police on himself with the intent of committing “suicide by cop.” When officers arrived, they saw a man armed with a knife who then advanced toward them “in a threatening manner.”(Underline added). Yup, criminals don't just fall down or get blown several feet backward when struck with a bullet.
Starting from a distance over 130 feet, the man first walked toward the officers and then accelerated into a “trot,” which was described as a “fast” and “rapid” pace. Still armed with a knife, the man ignored repeated commands to stop. When the athletic suspect reached approximately 55 feet from the officers, they opened fire. The suspect traveled another 37 feet toward the officers before falling.
So we have to consider that 21-feet was a bare minimum distance (assuming a holstered firearm) in which an officer could draw and fire, not the distance at which the attacker represented a threat. Kliem notes that the 21-foot "rule" is merely a beginning point, and you must also consider "such factors as pre-attack indicators, emotional arousal indicators, attention and perception influences, speed of assaults, firearms accuracy, action and reaction times, start and stop times, sprint speeds, the effect of uniform weight on performance and decision-making processes," as well as the effect of heightened emotional and physical stress on all of the preceding.
Obviously this distance/time can also vary based on whether the defender already has the firearm out, whether the aggressor is already moving, the training or ability of the people involved, and even the type of weapon. For instance, I'm confident that a competitive fencer could skewer someone in less than 1.5 seconds from a distance of 21-feet because the length of the weapon plus the fencer's arm is already 6 feet, and a lung will take that out to around 8-9 feet. Thus, a fencer would only need to move 12 to 13 feet before being in range of striking.
Aaron Cowan, writing at the Monderno blog, not only notes that the 21-foot rule not an actual rule, but argues it should be excised from the defensive lexicon.
Edged weapons, improvised weapons, sticks, bats, clubs, tire irons and cinder blocks; all have the ability to cause death or serious bodily injury with the intent to do so. If that intent exists, the actual type of chosen weapon is irrelevant. People like to talk about distance, as if it was the only deciding factor, well, it isn't. The "21 foot rule" isn't a rule at all, in fact the phrase "21 foot rule" shouldn't even exist and the only reason it does is because people parrot it from experts who aren't.He goes on:
Yes, I'll be blunt, anyone using that term as a serious training tool is not any sort of realistic expert. There are no bright line distances in self-defense, least of all a "21 foot rule" that the creator of the drill for which it is based, Dennis Tueller, never used the term at all. His drill was created to show how long it would take an officer to clear a duty holster with an edged weapon armed threat running at them. That time was averaged to 1.5 seconds or 21 feet. Some gun writer (the internet expert before such a thing existed) coined the term "21 foot rule" to justify the distance someone must be from you with a knife before you can shoot them.So what should we take away from Tueller's lesson? Warren Wilson writes:
This drill doesn't account for an officer already having their weapon drawn, the officer retreating or placing a barrier between them and the threat, or any number of other factors that would render it pointless. All in all, the drill only works to demonstrate distance vs. draw time and since there are much more effective and realistic ways to do that, its usefulness in training is questionable at best. Since it’s taken as gospel and almost always out of context, this "21 foot rule" is a dangerous mindset that can do much more harm than good. Distance is a factor, but often not the deciding one. Many other factors must be weighed before force is used and force can always be used with other options have failed, or cannot be attempted due to lack of time and/or distance.
His first point was “tactical alertness,” or what we might call situational awareness today. The quicker the defender recognizes the threat, the sooner he can take some soft of defensive action. Next, the ability and awareness to be able to move yourself to cover. That might mean an obstacle or anything between you and an advancing threat. Next, draw the firearm as soon as possible. Don’t wait any longer than necessary to get your sidearm in play. Issue verbal challenges immediately. Powerfully delivered commands may be enough to deter an assailant and will certainly aid in the officer’s justification to use deadly force if it comes to that. Finally, Mr. Tueller recommended, “consistent, repetitive practice,” in one’s draw stroke. The more skilled an officer is with his or her equipment, the greater their reactionary gap.