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by Peter Moskos

September 5, 2014

The 21-Foot Myth

It's long been "known" among police that anybody with a knife or edged weapon within 21 feet is a lethal threat. This so-called "rule" has long been a big pet-peeve of mine.

This anybody-within-21-feet-is-a-threat mentality does result in a lot of crazy people getting shot. And don't get me wrong, I have no problem with police shooting and killing people coming at them with knives. But the idea that anybody within 21 feet could be carrying an edged-weapon and is thus potentially a lethal threat? Get real. Even if the "21-foot-rule" were true, what are you supposed to do with this knowledge? You're a cop. Of course you're going to be dealing with people at a normal talking distance of a few feet.

The first problem with the 21-foot "rule" is that it assumes the officer doesn't perceive a threat. The scenario starts with a holstered weapon. Well if you don't perceive a threat that exists, that's a separate problem. But it doesn't mean you're justified in keeping everybody at a 21-foot distance. The second obvious problem with the "rule" is that it assumes that the man with the blade is a trained skilled stealth ninja (or at least an academy instructor-san much better than you, young academy grasshopper trainee, at hand-to-hand combat).

The relevant question is how close should you let a man with a knife get to you when you are in the drawn and ready position. Based on nothing but my gut experience (I'm sure somebody has better-formed answer), I would probably start shooting at about 6 feet. Maybe 10 feet if they're advancing in more a threatening manner. But of course it all depends on the situation: what kind of person? What kind of knife? How is the person holding the blade? (Blade facing back, arm-down, fist clenched means the guy may know how to use it.)

For small knives that don't make particularly good weapons (like a dinner knife or something without a bolster/finger guard), I'd be more than willing to take my chances defending myself and whacking the guy with my trusty 29-inch wooden straight baton (a far better offensive and defensive weapon than the now much more common expandable metal asp). And I'd be more willing to try and disarm the guy if I could come up from behind while the person with the blade is distracted by the other six officers on scene who are drawn down on him).

[And of course a man with a knife is exactly what the Taser is designed for even if it emasculatingly and shamefully used far more often for routine non-threatening non-compliance situations. Also, you should not mace a guy holding a knife, because then you have an angry blind guy with a knife.]

Here's the thing: most people police face with knifes are not well trained in "edged-weapon combat." They are A) crazy or B) cutting up their loved one. Sometimes both. But police rarely if ever face a trained evil ninja out to assassinate a police officer caught unaware (honestly, there are far easier ways to assassinate a police officer, if you so choose). So basically you have this whole police paranoia based on a situation that never happens.

I checked Officer Down and, since 2000, could find just four officers on patrol killed by an assailant with a bladed weapon: one domestic, one EP (aka: EDP or mental case), and two fatal fights after a foot pursuit. As you might guess, not one of these assailants was an a trained stealth ninja.

Best I can ascertain, only one officer in the past 14 years (Sault Ste. Marie Detective John Weir) could have been saved, maybe, I don't know, by keeping greater distance and being quicker to shoot. The other officers, rest in piece, died doing the job they had to do.

So why has the 21-foot rule persisted for decades despite little basis in fact or police reality? I don't know. I'd love to hear what you think. Could it be just another example of the conservative warrior mentality so pervasive (and usually counterproductive) in policing? Think of this: the instructor teaching hand-to-hand combat in the academy is the most aggressive threat-perceiving police officer out there perhaps (just hypothetical, er, based on my experience) having been pulled off the street and into the academy where he can't shoot another sue-the-city person (all of them technically justified, but still...).

So you get a perpetuating cycle where the paranoid cop too-quick to elevate a threat-level ends up teaching and scaring the next generation of police officers to adopt his code-red us-versus-them ideological world-view in which one must assume the worst about even seemingly non-threatening citizens.

Here's a good recent piece by Ron Martinelli which more scientifically analyzes and partially debunks the 21-foot rule, and inspired this post. If you're still with me, it's also worth clicking-through to the first link on this page.

Update: Based on a useful comment to this post, I also should have included blunt weapons and not just knives. Doing so brings the total number of police officers killed in the past 15 years with any relevance to the 21-foot-rule up to three police officers. It's also worth mentioning that I'm not looking at officers just injured. But we don't have those figures. And one can assume some relationship between fatal and non-fatal injuries.

So let's put the 21-foot-rule in perspective. In this same time period since 2000, as many officers (3) have been killed by a moving trains.

Six officers have been killed by animals: one by cow, one by spider, and one by bee; the other three from horses (interestingly, none by dog, the only animal often at the receiving end of a 21-foot mindset).

If one were truly interested in saving police lives rather than simply building police paranoia and mistrust of the public, we should look at the 515 law enforcement officers killed traffic fatalities. How many of these would have been prevented by officers wearing seat belts? And yet the same officer who won't wear his seatbelt because he claims it gets caught on his equipment (which, speaking from experience, is bullshit) will be quick to spout the absurdity that his life is endangered by anybody within 21 feet, in optimal conditions.

Also, it's come to my attention that the 21-foot-rule has now been upped to 30 feet.


Anonymous said...

1) Forgive me if this has been covered elsewhere on your blog, but just how many "crazy people" with knives are shot by police? You say "a lot," but I doubt that it really common at all.
2) Your thesis is that the "21 foot rule" is taken as gospel among police. The last two links that you cite, however, indicate that the law enforcement community is looking at this "21 foot rule" with critical eye. Police One is, I believe, the most widely read and referenced website for law enforcement nationwide. If this "debunking" was presented there in 2005 I can say that more than a couple of people read it and have used it to modify training and policy.
3) Pulling in statistics about officers killed with knives is meaningless. You could say that police are paranoid because they take precautions to guard against attacks that never happen, and I can say that because precautions are taken officers aren't attacked.
4) The argument that there is a pervasive problem with "warrior mentality" and a "code-red us-versus-them" attitude is such a load of crap. Are you being intentionally obtuse in citing these particular websites?
5) I like your blog. Keep it up.

BigGucciSosa said...

Wondering what your thoughts are on this police shooting of a knife-wielding man in St. Louis, shortly after the whole Ferguson thing.


While I think it's no doubt legally justified, I think that the cops could have shown a little bit more restraint before shooting the guy. He edges closer to the cops (never reaching anywhere near 6 feet from them), but never really charged at them and didn't yet seem to pose an immediate threat in my opinion.

PCM said...


1) I don't know how many mental people are shot by cops. Good question. But I will say (just based on my opinion) that a significant percentage of those by cops are mental.

2) As to training, I think there's a large gap between articles, training, and what cops on the street still believe and how they act. I still hear about the 21-foot-rule a lot. Recently.

3) Indeed, and they could be keeping dancing elephants away, too. You don't see many of those. But more seriously, it could be that officers are taking better precautions. And certainly that's part. But this whole "rule" is based on the idea that a person with a blade is a lethal threat at 21 feet. It forms too large a part of cop mentality, and it's based on a non-existent threat.

Better would be to treat cops how to read what a person says. Better would be for police to be trained in understanding signs of mental illness and autism. All this would protect cops better than the ninja possibility.

4) No. I just picked them based a quick google search so that people who have never of the color code and the "warrior mentality" could get some quick understand of what I was referring to.

5) Thanks!

PCM said...


I think the cop shooting was justified. I also think they probably shot a big too quick. But oh well. Would it have mattered if they waited one more second before shooting? I don't think the guy with the knife was going to stop. But who knows.

And I say this knowing that what I think from a video is pretty close to useless as to understanding perspective of the cop who was there. I give them the benefit of the doubt.

Gotti Rules said...

Hey Pete,
As you know, my shooting was with a man with a knife which took place in a Baltimore City rowhome kitchen/hallway area. The suspect was not a ninja but someone with mental illness. The incident started approximately 6 feet away from me when he then proceeded to come at me. I am not sure about the 21 foot rule, but 6 feet is way too damn close. One more foot and he would have stabbed me. I also believe that if the department hadn't upgraded from 9mm to 40 calibers, the suspect would have still been able to stab me. Speaking from personal experience, 6 feet is just way too close for comfort for me and as you know, our vests do not stop edged weapons.

PCM said...


Did you have your gun out before he went toward you? You know I'm not saying cops shouldn't shoot. I'm just saying 21 feet is crazy.

Any now I hear from another cop friend on facebook (not BPD) that many departments have declared that 21 feet isn't enough!

"In many law enforcement arenas 28 to 30 foot rule is being taught."

What the hell are you supposed to do with this so-called knowledge?! I guess lock the doors, roll up the windows, and wait to be called in.

Gotti Rules said...

Hey Pete,
Yes, I did have my gun out before he came towards me and I barely got out alive. Way too close Buddy! Also, during this situation I was trying to step back and shoot at the same time. I distinctly remember that I was walking backwards and tripping over stuff including my partner's feet while trying to shoot. At the academy you are never taught a walking shoot. I bet if you talk to officers who were being attacked I think some were trying to step back and get away from the suspect. Why isn't this taught? This kind of incident is more realistic than shooting at the range.
Miss you!

PCM said...

I remember when I was at Gunpowder Range (what a fabulous name to put a gun range, no?) we did have one (just one) paint-gun shooting drill. (What's that called again? I want to say semiotics... but that's not it)

It was *so* much more valuable than shooting at a target. But of course we only did it once. I guess because it was too labor intensive.

I still remember I tried to retreat-to-cover behind the engine-block of a car and... tripped over my feet walking backwards.

On the plus side I did practice my step-slid retreat after that.

Why isn't this taught is very good question.

Hey, unrelated, the weather just cooled about an hour ago. Come visit on some three day weekend! Waffle trucks await...

Gotti Rules said...

That paintball thing must have come after the time I was in the academy. The only semi-realistic training we had was on the Fatts machine. Once again, you are just standing there and it was like playing a video game.
Now that the weather is cooler, I will look at coming one weekend that I don't have to work. Maybe I will bring some crab meat with me.

PCM said...

Semunitions. That's the word. I assume they do that now, but not enough.

And we did FATs, too. Which was very useful. But we didn't do it enough. I hear (can't remember if it's NYC or Baltimore) that there's a new and improved version of FATs.

Momma Fargo said...

Not sure if I agree with all your points. I think each situation is one to take individually on the person and the weapon. Obviously there are different scenarios that could play out in the right circumstances. Several cases when we had suspects high with knives and acting irrational, we knew the threat prior to arrival and used less lethal to disarm them and then restrain them with physical force. Perhaps they don't show the knife scenarios in the right context, but the idea is that you may not have as much time to react. It's a good training tool. I don't agree with all the information out there as well, however, I don't dispute all of it either. If you have a person with a knife within 6 feet, however, under some instances, I would believe the officer is going to possibly get injured.

PCM said...

Could we just call it a 10-foot rule, then? And say it applies to a person you can see carrying a knife?

Knowledge is only useful if you can then alter your behavior based on that knowledge. How does the 21-foot-rule change one's behavior? I've never anything useful that can be done with this knowledge.

It's the whole fear of a non-existent threat that bothers me. The part I object to is paranoia building. Police have enough of that without help.
Yes, do teach how fast somebody can rush you and how long it takes to react. But that is not what cops take from the 21-foot rule. Look for tells and signs and indicators of aggression and instability. A cool, calm, trained assassin would win every time. Oh well. That is, to me, an acceptable risk for police to take.

It would be just as useful, and more true, to say: Don't ever stop at a red light or get coffee because somebody could walk up and shoot you. It's happened far more than the charging-ninja-with-a-knife scenario (which, again, as far as I know, has never happened).

What can you do with the knowledge? I don't want to get too fatalistic, but you do take your chances. Stay alert; stay alive. Use common sense. Trust your gut instinct. But do not, for the love of God, go through your life fearful of everybody within 21 feet. You can't live with that attitude. You can't police with that attitude. It shouldn't be part of police training.

Anonymous said...

Police are not as good at hitting people with wooden truncheons as they used to be.

campbell said...

How does the 21-foot-rule change one's behavior? I've never anything useful that can be done with this knowledge.

Martinelli does a good job pointing out that a lot of perception of the rule is not what was actually proposed by Tueller. But the drill does teach you things about what can occur at certain distances, your ability to react, your need for a plan, your need to have a weapon or option already deployed, etc. Sure, maybe a guy with a background in silat might have a feel for distance and timing when it comes to weapons but most people don't and certain types of drills are nice for illustrating a lesson in a visceral way that won't soon be forgotten.

campbell said...

Police are not as good at hitting people with wooden truncheons as they used to be.

Rodney King kind of ruined that for everyone. Seriously, some depts have policies that forbid the officers from even carrying an old school non collapsible straight stick except for riot control/public order type incidents.

If you want a really fraught discussion, did the totality of the circumstances of the Rodney King incident really merit the public response?

PCM said...

"certain types of drills are nice for illustrating a lesson in a visceral way that won't soon be forgotten."

Agreed, but I'm afraid the take-away lesson from the 21-foot-rule is that that guy with a knife is a lethal threat at 21 feet, which is not actually what the "rule" shows.

The important question is at what point do you shoot a guy with a knife coming in your direction when you are drawn and ready. *That* is what we need to know. Why do we not have such a figure?!

campbell said...

You're never going to know that for sure. There's just too many variables when shooting someone with a handgun in a dynamic situation. Like this video for instance.


That suspect was in fact fatally wounded but the way he was running around I initially thought the officer missed until I read the article and found out the suspect died a ways down the road after driving off. Watching something like that I think it's just about impossible to come up with something like "at 12 feet you're safe but at 8 feet you start shooting".

Anonymous said...

Your Officer Down search for deaths is misleading because you are not including blunt weapon attacks. Bad guy can easily charge an officer with a hammer, baseball bat or tire iron from 21 feet and kill her or him.

It is also misleading because you are only counting the officers who have died, rather than those who have been seriously injured but survived. Lethal force is justified in those situations.

Finally, you have ignored the fact that the 21 foot drill happens in optimal conditions (daylight, open space, no noise, no other subjects). Reality is much tougher.

PCM said...

Your first point is good. I'll look at blunt instruments and get back to you. I suspect it won't change much, though. But they should be included.

And indeed, being seriously hurt does matter. We just don't know about these cases. But one can assume there's some relation between fatal and non-fatal injury. And if the former is close to zero, the latter is probably pretty low.

Your final point is indeed why some academies are now teaching the rule as a "30-foot-rule." And that to me is a even more crazy.

PCM said...

Since 2000, 15 police officers have been killed by "assault" (which excluding guns, knives, and vehicles but includes most everything else, including blunt weapons).

Of those 15 -- and there's some subjectivity here, certainly, in how I classify the killings -- two officers have been killed by a assailant who *may* have been rushing the police officer.

So there have been two cases (three when one includes knives) in the past 15 years where observing a whatever-foot-rule *might* (and I emphasize might) have played a factor. (Police Officers Molina and Lee if you want to dig deeper, as my search may not have been complete).

I'm not counting assaults while a suspect was in custody. I'm not counting off-duty incidents. I'm not counting heart attacks. And I'm not counting cases where the officer made a choice to close in and engage a suspect (since the 21-foot-rule is about police being caught unaware by engaging suspects). Even with those we're still talking a small number, but it's irrelevant to the 21-foot-rule.

So let's put the 21-foot-rule in perspective. In this same time period (since and including 2000), the same number of officers (3) have been killed by a moving trains.

Six officers have been killed by animals: one by cow, one by spider, and one by bee; the other three from horses.

Eleven officers have died in training exercises.

And of course if one were truly interested in saving lives more than building police mistrust of the public, look at the 515 traffic fatalities. How many of these would have been prevented by officers wearing seat belts?

And yet the same officer who won't wear his seatbelt because he claims it gets caught on his equipment (which, speaking from experience, is bullshit) will be quick to believe his life is endangered by anybody within 21 feet, in optimal conditions.

PCM said...

What's odd, at least to me writing this, is there could be zero officers injured by this virtually non-existent threat and yet I won't change anybody's mind.

But in the long run, by building mistrust and further separating the police from the public, teaching officers a fake foot rule could cause more, not fewer, officers' injuries.

The message being taught isn't just "be alert" and "don't take your safety for granted." Those are fine and life-saving messages. Teach them and teach them well. There's enough real danger out there that we don't need to make up fake danger.