Read: How to actually fix America’s police
Social scientists have learned a lot about police-protester interactions and crowd behavior over the years. They divide police responses to protests into two main approaches. The first is a get-tough model of crowd policing, the sort championed by Trump, called “escalated engagement.” The second is a more moderated style called “negotiated management.” Many have objected that Trump’s approach is not legal, justifiable, or right. But escalated engagement has another problem—in general, it doesn't actually work.
In some instances, if police demonstrate an overwhelmingly powerful presence either before a riot breaks out or at its very early stages, it is indeed possible for them to control the situation. But it is next to impossible to predict exactly where and when a riot is going to break out—by the time enough police are mobilized and in position, it’s usually too late.
Much more frequently, a show of force by police can make a situation far worse. The protests of the police killing of Floyd have unfolded in a manner that has become too common in recent decades. Protests emerge in reaction to a police killing. A march or rally proceeds peacefully until the protesters block a street, go down an unplanned route, or stay in an area longer than expected. The police intervene, the protesters resist, and then a confrontation ensues, typically spinning into something neither side expected. Police can quickly find themselves outnumbered, their show of force producing the circumstance it was designed to avoid.
Increasing the number of police who are trying to contain protests—particularly with inexperienced officers from outside the community who are not trained for crowd confrontations and lack the discipline necessary for such situations—often fans the flames instead of tamping them down. When the National Guard or other troops are called in to help police crowds, they usually escalate the combative nature of the situation, or play a central role in producing a violent confrontation in the first place.
Negotiated management may not satisfy the president’s demand to “dominate,” but the evidence shows that it produces considerably less violence and destruction. In a 2004 study, I looked with a colleague at the equipment 400 police departments had stockpiled and the training they had received about how to handle crowds. Some departments were focused heavily on stockpiling repressive equipment—tear gas, smoke grenades, riot helmets, gas masks, riot batons—and providing their officers with the training to use it, while other departments had greater stores of assistive equipment—such as stretchers, ambulances, mobile communication devices, and lighting—and focused their training on understanding crowds and predicting and preventing riots. As it turned out, preparing for escalated engagement was a self-fulfilling prophecy: Repressive equipment increased the chances that a jurisdiction would experience a riot, and then that it would have additional riots. Assistive equipment had just the opposite effect.