(FORTUNE Magazine) – Let's be clear right up front that prisoner abuse is not to be confused with cooking the books. In trying to understand the Abu Ghraib mess by looking at spectacular failures of corporate management, we're comparing life-and-death matters with dollars-and-cents matters, and it's offensive to suggest they're entirely comparable. Yet there's no denying that anyone who has worked in a big organization nods his head while reading about the Iraqi prison debacle. A screwup so egregious you couldn't have imagined it does incalculable harm to a giant enterprise--we've seen it before. Managerial failures this mammoth are all different, but in a way they're all the same.

The great common feature they all share is the compromising of the police. That sounds odd in a corporate context, but it shouldn't. Every organization, including every company, has police. In the military their role is obvious: The military police are part of law enforcement within the armed services, and they operate the prisons in Iraq. In companies the police are just as important but have a different name: They're the auditors, part of the finance organization. When anything impedes the police, or even interferes with their incentives to do the one thing that they're supposed to do--enforce the rules--trouble follows. The only question is how bad it will be.

That means that in a company, if you want to break the rules, you must somehow neutralize the police. One can't help noticing that the man on trial with former Tyco CEO Dennis Kozlowski--and who, like him, was within hours of being convicted before the judge declared a mistrial--was Mark Swartz, Tyco's chief financial officer. The CFO in any company is the chief of police. Tyco asserts that Kozlowski cut Swartz in on the swag he was allegedly hauling out of the company precisely because he realized it was the only way he could get away with it.

In every single one of the other great corporate scandals of the past three years, the police chief--the CFO--was the critical link in what went wrong. Andy Fastow at Enron, Scott Sullivan at WorldCom, Timothy Rigas at Adelphia--if they had held firm, none of those disasters could have gone very far. At HealthSouth, incredibly, every CFO the company has ever had, except for the current, post-scandal one, has pleaded guilty to federal charges.

Sometimes the police get compromised without evil intent from anyone. That's what happened in the 1990s with those other corporate police, the outside auditors. Didn't it make a lot of sense for them to be consultants to the companies they were already auditing? After all, they were already experts on the companies' businesses. Why not really put that knowledge to work? It all sounded sensible until clients were paying the auditors $20 million in annual consulting fees and $4 million in audit fees, and the auditors--the police--realized they sometimes couldn't afford to be honest cops.

Something similar--police compromised without evil intent--seems to be what happened in Iraq. We don't know everything that went wrong at Abu Ghraib, but we know enough. We know that shortly before the prisoner abuse started, last October, the Pentagon overhauled procedures for interrogating detainees. The new procedures were supposed to involve the military police in the interrogation process as conducted by military intelligence officers--that is, the police were supposed to take on roles other than policing. It certainly appears no one was trying to do anything wrong--on the contrary, improved interrogation is something everybody wants. But suddenly a bunch of undisciplined, untrained, unsupervised MPs were apparently confused about whom they were working for--their own brigade or the military intelligence specialists or the CIA and civilian contractors involved in interrogation. And somehow, apparently in trying to carry out their new role, they were induced to do things they should never have done.

Of course, the abuse still could have been stopped had the MPs' direct supervisor, Brigadier General Janis Karpinski, been doing her job. True disasters always require that many things go wrong at once. But the big lesson is one that proclaims itself often when organizations damage themselves terribly: Your police have one job, and you'd better let them do it, make them do it, and not ever compromise them.