What a riot does achieve
For students at journalism college there is always that initial debate of what constitutes a story.
The hackneyed but good example is that if a dog bites a man it's not a story - dogs do that quite often. But if a man bites a dog, it is a story - because men, generally speaking, do not.
In other words the "story" is something that is unusual, rare and unexpected.
So what box do we put the Freddie Gray story in?
It's obviously a story - but it is none too rare, sadly not that unusual - and if you ask many in the black community, not in the least bit unexpected.
I heard one piece of commentary that more or less started "First there was Ferguson, now Baltimore"' - but in truth there has been a whole pile of incidents in between.
I haven't the space to list them all - the 12-year-old boy shot dead in a park in Cleveland, Ohio, the student left bloody and bruised at the University of Virginia, the man fatally shot eight times in the back in South Carolina, the 44-year-old chased down and killed in Tulsa, Oklahoma, after volunteer officer pulled a firearm instead of a stun gun.
And there are more, culminating in Freddie Gray dying while in the custody of Baltimore police, after his spinal cord had been virtually severed. It's unlikely you would sustain an injury like that simply by slipping as you stepped into the police wagon.
What the common features are of all these incidents is that the victims were black and the forces of law and order involved in them were for the most part white.
All of these stories made news on the day, and maybe even a bit of follow-up on day two and day three.
But have they stirred national debate, caused people to stop and reflect, led to serious - as President Obama has demanded - "soul-searching"? I am going to say not so much.
Which brings us back to the opinion piece that made the point that first there was Ferguson, then there was Baltimore. The writer is correct, insofar as they both resulted in looting, burning and vandalising - all playing out on our screens last night.
How could you not feel sickened to see some poor shopkeeper's life's work go up in flames, or being taken away in greedy armfuls by the lawless mob?
There was something almost grotesque about sitting and watching for an hour or so the looting at a CVS pharmacy store as people very casually wandered into the store and wandered out with their arms full.
And not a policeman in sight. If I were on the board of CVS I would be asking the authorities in Baltimore some pretty searching questions.
And some pretty searching questions are being asked again today about American society - What to do? How to put things right?
This has been a huge story because in 21st Century America you don't really expect the need to impose night-time curfews.
From tonight in Baltimore, unless you are going to work or you have a medical emergency, you are banned from being outside.
You don't really expect to see Humvees and the National Guard on patrol in one of the larger cities in America.
It's astonishing. The cable channels are full of it, Washington has sat up and taken notice. If you could market hand wringing, you'd make a fortune.
But here is the morally uncomfortable bit - is it the death of Freddie Gray that has caused everyone to sit up and take notice, or is it the rioting?
From the hapless Baltimore mayor through to the president the point has been made - rioting achieves nothing.
But, sadly it has. It has caught people's attention - because it has conformed to the journalist's law of what makes a story - it is rare, unexpected and unusual.
Perhaps the lesson is we need to take more notice of things that lead to the riots and sense of alienation by disaffected young African-Americans.
The white cop assaulting or shooting a black man may not be that unusual, but it has already led to dire consequences for those living in Ferguson and in Baltimore.