What 'the blue wall of silence' means for police reform

Economics professor Jean-Pierre Benoît on Bayesian reasoning, the George Floyd murder and the need to speak out against brutality

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George Floyd was a father, truck driver and mentor. He died last year, when one of the four police officers involved in his arrest, Derek Chauvin, knelt on his neck for over nine minutes. Floyd was unarmed and accused only of attempting to use a counterfeit twenty-dollar bill in a local convenience store. As he lay dying, other officers involved stopped passers-by from intervening, but were unable to stop video footage of the event from being uploaded to social media, where it was swiftly shared across the globe.

In the weeks that followed, unrest in Minneapolis sparked action around the country. Tens of thousands of Americans marched against unchecked police brutality and Floyd’s cry of ‘I can’t breathe’ became an unofficial slogan for the Black Lives Matter movement.

Along with the protests came discussions about the future of policing. Is it possible to reform a police force where a man like Chauvin thrived? Or should the police be defunded entirely, with money channelled towards social work and community care instead? Suddenly, these once radical ideas were becoming part of mainstream American discourse.

One of the major hurdles to reform is how police respond – or don’t – to accusations of corruption. Often, allegations are met with silence from other officers, who will almost never testify against each other in court.

Professor Jean-Pierre Benoît addressed the issues surrounding the wall in his lecture ‘The blue wall of silence, the killing of George Floyd, and Bayesian reasoning'. Here’s what it means for the debate:


Just a few bad apples?

Derek Chauvin was convicted of second-degree unintentional murder, third-degree murder, and second-degree manslaughter. We might look at this and feel that at least justice has been served, but unfortunately Chauvin is the exception. Police officers are rarely convicted of serious crimes, or even internally disciplined. Chauvin himself had eighteen official complaints of misconduct on his record, and was still a serving officer, still allowed to carry a gun.

“A pervasive code of silence” influences both honest and corrupt officers and leaves even the ‘good’ cops reluctant to report brutality.

What does a case like Chauvin’s tell us about policing in modern America? Is it evidence of broader corruption, or just a ‘bad cop’ gone rogue? Many people will claim that the vast majority of cops are ‘good’ and that we shouldn’t let public opinion be tainted by ‘a few bad apples’. But if this is the case, why aren’t the police doing more to police themselves?

The blue wall of silence refers to police officers’ well-documented refusal to speak out against their own. From procedural errors, to serious crimes, officers will almost never report a colleague’s misconduct. In the court room, officers rarely testify against each other, often going so far as to perjure themselves by feigning ignorance. Police unions too, are notorious for defending officers, seemingly regardless of their actions.

The wall gets its name from the blue uniforms worn by American officers, but this is not a uniquely American phenomenon. Nor is it a new one; The City of New York Commission to Investigate Allegations of Police Corruption and the Anti-Corruption Procedures of the Police Department, concluded in 1994 that “a pervasive code of silence” influences both honest and corrupt officers and leaves even the ‘good’ cops reluctant to report brutality.

Why does it exist?

For many officers, the police force is a brotherhood. A family. Only other officers understand the reality of the job, the brutality of the streets and the danger they put themselves in every day. Essentially, only cops understand cops. This belief has led to an insular culture, where protecting one of their own is second nature. Those who do speak out are often ostracized, which makes other officers less likely to come forward. Some former officers have even claimed they were harassed or threatened after testifying against a colleague.


The wall is damaging to police and public trust

These silent tactics are often so entrenched that they have become counterproductive. The wall is so infamous, it has come to be expected. Often, investigators will factor this in and essentially ignore positive police testimonies or disregard union statements. The public too has largely become inured to these statements. Clearly, the more unilaterally officers are defended, the less weight those defences carry.

Of course, there is also a moral cost for many officers. People join the police force to catch criminals, don’t they? It can be extremely distressing for officers to realise that sometimes those criminals are within their own ranks.

What Chauvin’s defence tells us about police brutality

We can pick a case like Chauvin’s apart very logically and use that logic to tell us something about police brutality more broadly. Clearly, when an innocent person dies at the hands of an officer, something has gone very wrong. But could it have somehow been an understandable mistake?

Often, in cases like these officers will use the ‘split second’ defence, claiming they had just moments to act and were afraid for their lives. Or they might claim the victim was holding something – a phone, a pack of cigarettes, even a toy – that looked like a weapon.

In reality, these defences have a damning. If deaths like George Floyd’s can be explained away as having been somehow ‘reasonable’, then where does this leave us? Are we to conclude that a ‘good’ cop acting reasonably is just as likely to kill an innocent person as a ‘bad’ cop?


Video evidence makes all the difference

Chauvin’s team used all these defences and more. But in this case, everything came back to the video. We can clearly see Chauvin’s knee on Floyd’s neck. Floyd is handcuffed, distressed, calling out for his mother and unable to breathe. Even after he stops moving, Chauvin keeps his knee there for another two or three minutes. It is indefensible.

Chauvin knows he’s being filmed, but does he look worried? Does he modify his behaviour for the camera? No. The reality is that Chauvin doesn’t worry he’s being filmed because he does not believe he will be punished.


There will be no reform while the wall exists

Protestors didn’t take to the streets because they believed Chauvin was one bad apple. They marched against systematic injustice and the culture of silence that allows officers like Chauvin to exist. Chauvin behaved as he did because nothing in his training or work environment suggested to him that he would face consequences for brutalising an innocent black man.

In Minnesota, the blue wall of silence did wilt during Chauvin’s trial. The police chief acknowledged that Chauvin acted wrongly. This must continue if public trust is ever to be restored. Otherwise, there is no difference between ‘good’ and ‘bad’ cops, and reform will remain impossible.

This wilting of the blue wall came tragically late. If most people had eighteen complaints against them, they would be severely disciplined, if not fired. Why is this not the case for police officers? Why isn’t the force throwing these abusive officers, before someone dies?

How can we use Bayesian reasoning to assess Chauvin’s case?

Bayesian inference is a method for updating the probability of a hypothesis as new information becomes available. If we want to assess whether an officer who killed an unarmed person was acting criminally when they killed someone, we can interrogate two areas: our understanding of the specific events that led to the death and our existing beliefs about the American police force. 

Firstly, we need to ask what is the probability that a police officer would kill an unarmed person when acting reasonably? How much less likely is this than a police officer killing an unarmed person when acting criminally? To the extent that a reasonable officer is less likely to kill an unarmed person, the facts themselves tend to point to criminal behaviour.

However, we must also look beyond the event itself. Let’s say we take the view that most police are ‘good’ -- the defense is often counting on this being the starting point of the jurors (and the public at large). Arguments like the ‘split-second’ defence, or claims the victim was on drugs, can cloud the issue, leading jurors (and other observers) to lean heavily on their pre-existing beliefs and decide the officer was more likely to be reasonable than criminal – or at least not criminal beyond a reasonable doubt.

But in the case of the killing of Floyd, there is the video. No matter how favourable one’s view of the police might be, there is no denying Chauvin’s brutality. The video is crystal clear, and the first half of the Bayesian odds is too strong to be overturned by the second. Chauvin is clearly guilty.




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