This article was contributed by Warren Wilson, a lieutenant with metropolitan police department in Oklahoma. He is a former SWAT team leader, current firearms instructor and writer. He has been a full-time law enforcement officer since 1996.
For the uninitiated, “derp” is a word that’s been embraced by the shooting and self-defense community to describe a foolish act or thought. A “derpism” is a widely believed but deeply flawed non-truism. If derpisms were BBs, there would be enough in the self-defense and use of force communities to fill a box car. The “21-Foot Rule” is one such derpism. It’s a perfect example of an amazing data point being bastardized into something it was never intended to be.
Dennis Tueller was a firearms instructor in the 1980s training police officers at Salt Lake City PD. After running some students through a seven-yard draw-and-fire drill, one of them asked him, “how close is too close?” in reference to using deadly force against suspect with an edged weapon. Tueller just didn’t have an answer for him, so right then and there, he started experimenting.
Since they’d already been working at seven yards, that distance was chosen as the starting point. A second and a half was, and is, considered an acceptable amount of time to draw and accurately fire two rounds at seven yards for law enforcement students. Tueller found that one and a half seconds was coincidentally about how long it took for one of his students, irrespective of gender or size, to cover seven yards (21 feet). Tueller referred to this distance as the “Danger Zone.” Three years before Kenny Loggins made a fortune with the musical version of that phrase, Tueller published his findings in a 1983 issue of SWAT magazine article called, “How Close is Too Close?” The Tueller Principle became an all-but-mandatory point of instruction in law enforcement academies soon thereafter.
Derp to the Left of Me, Derp to the Right of Me
This groundbreaking, if informal and impromptu, study led to many great things in law enforcement training. Massad Ayoob began using the principle in classes, dubbing one particular exercise the “Tueller Drill.” The term “Reactionary Gap” (which encourages the defender to consider not only distance, but officer/offender capabilities, obstructions, etc. when judging a potential threat) can be traced back to studies of Tueller’s work.
In the midst of all this great progress, like a really dumb phoenix rising from the ashes of derp, someone, somewhere came up with “The 21-Foot Rule.” 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.
What We Were Supposed to Learn
What was Dennis Tueller trying to teach us with this 21-Foot Principle? By reading the original article and watching subsequent interviews with him, one can easily glean what Mr. Tueller had in mind.
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.
All That is Necessary for The Triumph of Derp
Not only is there a tactical lesson in this story, there is a training lesson. The Internet has only exacerbated the information overload/wisdom deficiency problem we have in the training industry. My buddy, Chuck Haggard, has been a legit trainer in all things use-of-force for decades now. I once cautioned him about arguing with an ignorance enthusiast on the Internet “If you gaze too long into the derp, the derp surely gazes into you.” His response was classic Chuck: “All that is necessary for the triumph of derp is that good men do nothing.” Well, here I am doing something. There have been a lot of great articles on this topic over the decades, but I guess we’ll keeping writing them until it sticks. You are now part of the solution. Next time you hear the term, “21-foot rule” in social media, do your part and explain the 21-Foot Principle or at least cringe, because you know better.