The most-chilling image to emerge form the grand-jury inquiry into the death of Michael Brown comes in Officer Darren Wilson's graphic recollection of Brown's last moments.
"I remember looking at my sights an firing," Wilson told the jury. "All I see is his head and that's what I shot."
It's a bull's-eye view of the kind that too often ends with an unarmed black youth killed or maimed by a white policeman whose lethal reaction is fueled by fear.
Any situation seems ominous when seen through the narrow perspective of a gunsight. Every move is menacing, every gesture threatening.
Viewed through a gunsight, 12-year-old Tamir Rice looked armed and dangerous to a policeman answering a call about a youth sene carrying what looked to the caller like "a fake gun." His pellet gun proved to be fake. His wounds proved fatal.
John Crawford was fatally shot by police last year in a Walmart in Beaver Creek, Ohio, when police thought the toy gun he was holding next to the store's display of toy guns was real.
In September, Levar Jones was wounded by a South Carolina State Trooper Sean Groubert who panicked when Jones reached into his car for the license Gourbert had asked him for.
It was,in all other respects, a routine car stop. But he spent 12 hours handcuffed to a gurney in the hospital even though he had done nothing wrong. He was lucky. He survived.
Amadou Diallo was not so lucky. The African immigrant died in a doorway when he was hit 19 times in a hail of bullets fired by four New York cops in 1999. He died for the same offense that led to the Jones shooting - possession of a concealed, deadly wallet.
Those are just a few recent scenes form the moving picture painted in a report last month from the investative jounrliasm website ProPublica. It found that young black males are 21 times more likely to be fatally shot in confronations with police than young white men.
This history that forms a back-drop for the demonstrations that have broken out form L.A. to D.C. this week. To the protesters, this ruling is just one more example form a justice system that seems all-too anxious to justify these injustices.
The easy and thoughtless response to these demonstrations would be to link them all to the lawlessness that broke out in Ferguson.
The looters and arsonists need to be found and prosecuted. But they can't be allowed to overshadow the grave concerns raised by this and similar incidents.
The grand jury has ruled that Wilson's fear justified the fatal shooting. They might be right. They heard testimony of a violent confrontation between Brown and Wilson before the shooting.
But eyewitnesses, particularly Dorian Johnson who was with Brown that day, contradict Wilson's claim that Brown punched the officer before Wilson fired the first two shots.
The proper forum for resolving a case with that many key fact sin dispute is an open court. Most prosecutors would have opted for a public trial before a jury that would hear testimony form both sides. Instead, this jury was led to an inevitable conclusion by St. Louis County Prosecutor Bob McCulloch.
McCulloch seeemed bent on exonerating Wilson. How often do we see a prosecutor position himself as a neutral party in a grand jury presentment? Why did he spend so much time trying to impeach what were essentially prosecution witnesses?
And why didn't McCulloch offer the grand jury the alternative of a lesser offense such as recklessly endangering another person or voluntary homicide?
The chances that ajury would convict an on-duty cop of the malicious killing of a suspect he had never before are remote.
But, if the justice system is to maintain at least the veneer of fariness, cases like this should be resolved in a forum that calls for vigorous advocacy from both sides.