I don't think I will ever forget the images live streamed from a phone in the car of that young woman in Minnesota with her companion slumped in the seat beside her and an unseen policeman's gun still poking through the window and she tried to tell the cop, in shock and disbelief, her boyfriend had been reaching for his licence.
Evidently, he had told the officer he had a gun, as licensed owners are supposed to do when approached by the police, so I dare say a case can be made in the cop's defence. In any case, a policeman in America has only to say he feared for his safety, I think, regardless of how unprofessional his fear may be.
America has a problem because blacks, and indeed all fair-minded Americans, know very well that if that young man in the car had been white, he would still be alive.
The incident was just one of several lately that have been recorded on cellphone cameras as they happened and seen by everyone. They sent many many far-minded Americans into the streets to stand behind banners saying, "Black Lives Matter" - until at one such demonstration in Dallas, a deranged ex-serviceman went much further, sniping and killing police on duty.
At the Trump convention (not the Republicans' really) every speaker I heard had a great deal to say about the dead police. They said not a word about the man shot in Minnesota, or the one we saw shot by police as he lay on the street in Baton Rouge, or any of the incidents relayed by cellphones recently. Not a word.
The Democrats invited to their convention the mothers of black youth such as Trayvon Martin, shot by scared white men acting in the name of the law. The women filed into the stage and a few of them spoke briefly. But not much more was said about "black lives matter". It would not have helped the convention's main purposes, one of which was to confront Trump's biggest lie: that America is no longer "great".
The other was to deliver a dire warning to the country. Former CIA Director and Defence Secretary Leon Panetta, who has served Republican and Democrat Presidents, explained why Trump is dangerously unfit to be given charge of America's military might. A real businessman and former Mayor of New York, Mike Bloomberg, not a Democrat, said, "Most of us who have created a business ... don't pretend we are smart enough to make every big decision by ourselves. Most of us who have our names on the door know we are only as good as our word. But not Donald Trump.
"Throughout his career, Trump has left behind a well documented record of bankruptcies, thousands of lawsuits, angry shareholders and contractors who feel cheated and ... customers who feel ripped off. Trump says he wants to run the nation like he's run his business. God help us."
Was America listening? There's madness around. Some of it may be anger and fear but mostly it looks like fun. Mindless, reckless, foolish fun.