On Wednesday, the city of Memphis remembered the life of Tyre Nichols, a young man who was beaten by at least five Memphis police officers and died three days later. Stories like this are terrible, they’re relentless, and they renew one of the most contentious debates in the nation: Are there deep and systemic problems with the American police?How we answer that question isn’t based solely on personal experience or even available data. It often reflects a massive partisan divide, one that reveals how we understand our relationships with the institutions we prize the most — and the least.Every year Gallup releases a survey that measures public confidence in a variety of American institutions, including the police. In 2022, no institution (aside from the presidency) reflected a greater partisan trust gap than the police. A full 67 percent of Republicans expressed confidence in the police, versus only 28 percent of Democrats.Why is that gap so large? While I try to avoid simple explanations for complex social phenomena, there is one part of the answer that I believe receives insufficient attention: Our partisanship tends to affect our reasoning, influencing our assessments of institutions regardless of the specifics of any particular case.Here’s what I mean. The instant that a person or an institution becomes closely identified with one political “tribe,” members of that tribe become reflexively protective and are inclined to write off scandals as “isolated” or the work of “a few bad apples.”Conversely, the instant an institution is perceived as part of an opposing political tribe, the opposite instinct kicks in: We’re far more likely to see each individual scandal as evidence of systemic malice or corruption, further proof that the other side is just as bad as we already believed.Before I go further, let me put my own partisan cards on the table. I’m a conservative independent. I left the Republican Party in 2016, not because I abandoned my conservatism but rather because I applied it. A party helmed by Donald Trump no longer reflected either the character or the ideology of the conservatism I believed in, and when push came to shove, I was more conservative than I was Republican.But my declaration of independence wasn’t just about Trump. In 2007 I deployed, relatively late in life, to Iraq as a U.S. Army judge advocate general, or JAG. Ever since I returned from my deployment, I’ve been gradually shedding my partisanship.The savagery of the sectarian infighting I saw in Iraq shocked me. I witnessed where mutual hatred leads, and when I came home I saw that the seeds of political violence were being planted here at home — seeds that started to sprout in the riots of summer 2020 and in the Trump insurrection of 2021.As American polarization deepens, I’ve noticed unmistakable ways in which committed partisans mirror one another, especially at the far edges. There’s even a term for the phenomenon: horseshoe theory, the idea that as left and right grow more extreme they grow more alike. When it comes to the partisan reflex — the defense of “my people” and “my institutions” — extreme partisans behave very much like their polar opposites.And make no mistake, respect for police officers has long been vital to the very identity of conservative Americans. Men and women in uniform are ours. They’re part of our community, and — as the Blue Lives Matter flags in my suburban Nashville neighborhood demonstrate — we’ve got their backs. (Mostly, anyway. Lately, the Capitol Police and the F.B.I. do not feel that same support.)There are good reasons for respecting and admiring police officers. A functioning police force is an indispensable element of civil society. Crime can deprive citizens of property, hope and even life. It is necessary to protect people from predation, and a lack of policing creates its own forms of injustice.But our admiration has darker elements. It causes too many of us — again, particularly in my tribe — to reflexively question, for example, the testimony of our Black friends and neighbors who can tell very different stories about their encounters with police officers. Sometimes citizens don’t really care if other communities routinely experience no-knock raids and other manifestations of aggression as long as they consider their own communities to be safe.Shell casings are marked at the front door of the apartment of Breonna Taylor, who was fatally shot during a no-knock raid by police officers in Louisville, Ky., in 2020.Louisville Metro Police Department, via Associated PressAt this point you might be asking: When is the left reflexively defensive? What institutions does it guard as jealously as conservatives guard the police?Consider academia. Just as there is a massive partisan gap in views of the police, there is a similar gap in views of higher education. According to a 2022 New America Survey, 73 percent of Democrats believe universities have a “positive effect” on the country, while only 37 percent of Republicans have the same view.Yes, this is in part a consequence of anti-intellectual strains on the right and among right-wing media. And this conservative mistrust of higher education (and secondary education) is causing it to turn its back on free speech and instead resort to punitive legislation, such as Florida’s recently passed “Stop Woke Act,” which a federal court called “positively dystopian” and unconstitutionally “bans professors from expressing disfavored viewpoints in university classrooms while permitting unfettered expression of the opposite viewpoints.”But that’s not the whole story. The nonpartisan Foundation for Individual Rights and Expression — of which, full disclosure, I was once president — has tracked over 900 incidents since 2001 where scholars were targeted for termination or other penalties for speech that was protected by the First Amendment or by conventional principles of academic freedom. In 2021 alone there were 111 attempts to penalize professors for their speech, and almost 70 percent of those attacks came from the left.I spent years litigating campus free speech in court. It was frustrating to file successful case after successful case — often challenging policies that existed in campuses across the country — only to be told time and again that there was no systemic problem with free expression on campus, that these were merely isolated incidents or a product of youthful overenthusiasm, of kids being kids.No one should pretend for a moment that there is any kind of moral equivalence between university censorship and fatal police violence. The stakes on the streets are infinitely higher than the stakes in the classroom. But there is still a common problem: Our repeated assumptions that those on our team might make mistakes or overstep, but those on the other team are deliberately malevolent.I should know. I used to fit that partisan mold. As a conservative, I could clearly see the problems in American universities. After all, it was my tribe that disproportionately faced penalties and discipline. When it came to the police, however, I was skeptical. I knew there were some bad apples. But was there a systemic problem? I was doubtful.I have since changed my mind, but it took shedding my partisanship and applying my principles to allow me to see more clearly. Fundamental to my worldview is the belief that human beings possess incalculable worth, but that we are also deeply flawed. No person or institution can be completely trusted.Thus powerful people and powerful institutions must be held accountable. If you combine authority with impunity, then corruption and injustice will be the inevitable result. If I could see this reality clearly in institutions on the left, why couldn’t I see it on the right?The police, after all, possess immense power in American streets, often wielded at the point of a gun. Yet the law systematically shields them from accountability. Collective bargaining agreements and state statutes provide police officers with greater protections from discipline than almost any other class of civil servant — despite the fact that the consequences of misconduct can be unimaginably worse. A judge-made doctrine called qualified immunity provides powerful protections against liability, even when officers violate citizens’ civil rights. Systemic police corruption and systemic abuse should not have been a surprise.The Minneapolis police officer Derek Chauvin subdues George Floyd during an attempted arrest in 2020.Darnella Frazier/Agence France-Presse — Getty ImagesHow do we fight past our partisanship to become truly curious about the truth? For me, the answer started with the first principle of my conservatism: Human beings possess incalculable worth. If that is true, and my neighbors and fellow citizens are crying out about injustice, I should hear their voices and carefully consider their claims.My initial inability to see the truth is related to the second principle, that human beings are deeply flawed. I had no trouble applying that principle to my opponents. But it also applies to those I generally admire. It applies to police officers. It applies to me.The lesson I’ve taken has been clear: Any time my tribe or my allies are under fire, before I yield to the temptation of a reflexive defense, I should apply my principles and carefully consider the most uncomfortable of thoughts: My opponents might be right, my allies might be wrong and justice may require that I change my mind. And it may, in all likelihood, require that I do this again and again.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: email@example.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.