The senseless slaughter of 21 innocents by a deranged shooter in a Uvalde, Texas, schoolroom remains incomprehensibly awful. The July 17 comprehensive report by the Texas House of Representatives sheds light — and more pain — on that terrible day. In particular, it presents in no uncertain terms the epic failure of responding law enforcement to quickly neutralize the shooter and stop the carnage.

The House report is thorough, factual, and even-handed. In all respects, it reads like a search for understanding, not blame. It identifies numerous factors that left the door open (literally) to the predator and then provides a minute-by-minute chronology of events from the moment he entered Robb Elementary School.

It reveals the shocking fact that although 376 armed and trained federal, state, and local law enforcement officers gathered at the school, they inexplicably took no action to confront the shooter for 73 long minutes after the initial shots were fired. In that time, wounded children bled and died.

As expected, public condemnation has been swift and uncompromising. Heads are rolling. Careers and reputations are ruined. Infinitely worse, there is the renewed and irreconcilable anguish of parents who now realize that their child might have been saved, and the lifelong burden of guilt carried by those who failed to save them.

The report characterizes the response failures as systemic and the decision-making as egregiously poor. It acknowledges the bewildering absence of initiative and proactive leadership, and it lists a litany of training deficiencies, tactical misjudgments, and procedural non-compliances.

The Texas House report’s criticisms are all valid and all are important. But for all of its specificity, it provokes the single most important question: Why? How is it possible that in that hour of evident, ongoing crisis — with an active shooter in a school room, and known casualties, and frantic 911 calls from terrified children — armed and trained officers stood by impotently? Did they simply lack the courage to act? Were they frozen by fear?

No. Of course, there was uncertainty and fear, but it stands to reason that their paralytic indecision was due at least in part to their innate recognition that a wrong decision would affect their lives in ways perhaps more lasting than a predator’s bullets.

Consider the implicit contract now in place between Americans and law enforcement. We expect our police officers to put themselves in harm’s way, without hesitation, whenever duty calls. We expect them to make split-second decisions, and we know that in such pressure-packed circumstances mistakes or misjudgments are possible and success is never assured. Nevertheless, we’ve also made it crystal clear that if the outcome is bad, we will hang them out to dry.

Worse, they know that their actions will be judged by people under no pressure and with all the time in the world, with perfect 20/20 hindsight.

Remember Kim Potter, the Minneapolis police officer with a 20-year spotless record who in one perilous instant mistakenly drew and fired her service weapon instead of her taser? Hers was a tragic mistake, irreversible and heart-wrenching — but in a courtroom months later, the prosecuting attorney convinced a jury that such very human mistakes cannot be tolerated.

Potter now languishes in jail, while her righteous prosecutor has presumably returned to her protected and comfortable personal life.

Now imagine for a minute that the first officers on the scene at Robb Elementary had burst through that classroom door and the trapped shooter reacted by opening fire on the cowering children. Had that happened, the recriminations would surely have followed: Those reckless cowboys came in guns blazing, and now our kids are dead.

We have no idea if that scenario crossed the minds of the officers stalled outside the horror-filled classroom. But the hard reality of routinely unreasonable, uncompromising deprecation of police in the post-Ferguson and post-George Floyd era surely influences every police officer’s behavior, every day.

Make no mistake: The law enforcement personnel in that Uvalde school failed dismally. But that outcome didn’t happen in a vacuum. We, the public at large, must recognize that in our zeal to protect against excessive police violence, we have unwittingly altered our fundamental relationship with those police officers.

It’s an untenable arrangement. Law enforcement demands courage and commitment at a level few of us are willing to offer. The newly upended relationship between Americans and our police is prompting their reluctance to engage in potentially volatile situations, it surely contributes to increased crime rates, and in the long term it will discourage qualified and capable men and women from careers in law enforcement.

If we expect police to have our backs, we need to have theirs.