A Little Knife

A Little Knife

By Chief Joel F. Shults, Ed.D

President Biden famously said that when confronted with an unarmed person with a knife, police should shoot them in the leg. When confronted with an edged weapon – knife, shovel, or broken bottle – an officer must make dozens of calculations and predictions as to the lethality of the weapon and the bearer of that weapon.

The decision of how to gain compliance is a complex one. The factors that go through an officer’s conscious and subconscious mind involve complex legal and regulatory standards as well as primitive survival responses to basic brain functions governing the fight, flight, or freeze neurochemistry. Critics are saddened when a mentally disturbed person with such a weapon is killed by police. The police are saddened, too. But knives kill whether the wielder is in their right mind or not.

The tensing of muscles, micro-expressions flashing in a millisecond, a subtle angle of the shoulder or foot, or the change in breathing can signal – in context – resistance or aggression. Athletes are given great honor for such instincts in boxing or swinging at a pitch; as well as great latitude for failure. Interpreting and reacting to the complex physics of a pitched baseball a third of the time makes a batter a hero! By contrast, one perceived mistake by a police officer ends a career even if, were all possible facts known, he or she made a reasonable decision.

The first question that seems to capture the attention of critics is the size of the knife. Perhaps common sense would seem to dictate that a large knife is more dangerous than a small knife, with the scale of dangerousness diminishing with the size of the blade. This assumption is not true. Some considerations are the vulnerabilities of human anatomy to a stab or incision, and the maneuverability of a blade in human hands, rather than how big or frightening the bladed weapons appears. Multiple areas of the officer’s body are vulnerable to pain, disability, and mortality. We don’t have to go past the 9/11 airline hijackings to remember the lethality of a blade as small as a box cutter.

If an officer is killed or disabled, the risk to others is multiplied. Officers are sometimes criticized for their efforts at self-preservation, but their purpose is not merely to survive, but to remain active in resolving the threat to others. Having an injured officer to be rescued, or having a perpetrator now have access to the officer’s equipment, raises the danger level of the event for everyone.

The human heart is typically less than three inches from the skin. Stab depths are affected by the elasticity and compression of the body so that the length of the blade is not the limit of the depth of a stab wound. Although ballistic material is often worn by police officers, the material is designed to spread the force of a blunt bullet, not a thin blade. Therefore a knife could penetrate a bullet-resistant vest that can stop a bullet. The fact that an officer has tools, training, and protective gear for dealing with violent resistance does not, therefore, justify any concession of advantage to the lawbreaker.

Add to the risk of a single fatal stab, the vulnerability of eyes, arteries, and fingers to a slashing incision, one can imagine that a police officer attempting to gain control of a resisting subject who has a blade might be distracted or disabled by pain, blindness, or dysfunction with one intentional or accidental slash or stab.

The shoot them in the leg hypothesis is not supported by physics or human biology. The swiftness of a knife-wielding person would obviously be affected by the size of his blade. A long samurai sword swung in an arc would take longer to maneuver than a paring knife. This makes the paring knife potentially more lethal than the sword in close encounters. A ten-year-old little league pitcher can hurl a baseball at 50 MPH. A thrusting or swinging motion with a blade is very fast and can be happening from literally an infinite number of angles. Add to that any running motion that might be a part of resistance or attack, even assuming an additional 3 MPH of body motion, makes any police attack on the knife as a target highly unpredictable.

Not only is hitting the target an uncertainty, but the effectiveness of an accurate strike also is not certain either. Resisting subjects may be under the influence of alcohol, other drugs, or just adrenaline. All of these chemicals reduce response to pain. This means that a strike must not merely hurt enough for a person to drop their weapon, the strike must be powerful enough to break the anatomical structure enough to stop the control of the attacker over the weapon.

Meanwhile, a motivated aggressor not limited to fighting just with his or her knife, but with the other hand as well as feet and head and teeth. Moving in close enough to do anything suggested by a non-lethal response presents the officers with too many threat variables to effectively control. I liken it to trying to reach into a blender to stop the blades from spinning without getting cut. It must be noted that even deadly force is uncertain, as in many documented cases of attackers’ continued aggression after sustaining a deadly injury. Once again movies have convinced us that people who are shot fall dead immediately, which is rarely true.

The TASER, or other electronic control device (ECD), is not appropriate as the first choice against an edged weapon. Best practice is to deploy an ECD against a person with a deadly weapon only if at least one other officer is present with lethal cover (i.e. with his or her firearm drawn) in case of ECD failure. ECDs have limitations and conditions for success that make the outcome of their use too unpredictable to be used as the primary option when facing a bladed weapon.

Why use lethal force against edged weapons? Because knives are deadly.