Disturbances centred on the east Belfast Catholic pocket of Short Strand are, alas, nothing new. In the 1920s Irish nationalist leader Michael Collins complained of attacks on its residents by armed loyalist mobs. In the local Catholic church, soldiers had to set up a machine-gun post in the Mother Superior's cell. Every few decades things flare up again: nine years ago disorder broke out and lasted for months. It is the scene of division and high segregating "peacelines", a misnomer if ever there was one.
The district's barbed wire and industrial-strength steel mesh are just five miles away from Holywood in County Down, the pleasant seaside town where Rory McIlroy honed the golfing skills which won him the US Open at the weekend. The elation generated by his victory was still in the air when news of the latest rioting, the worst for years, came through. Suddenly headlines about sporting excellence in Northern Ireland were displaced by others about backstreet violence.
What is not apparent from the television pictures is that the trouble at Short Strand, and a few other flashpoints, is highly localised. It is also not obvious that these outbreaks are becoming more and more of a rarity, or that the vast majority of the population has left these things behind.
There is a new atmosphere, and there are new relationships, which mean that many such flare-ups are avoided. One-time hard men, including both loyalist and republican ex-prisoners, now work together behind the scenes to prevent trouble.
These networks of former enemies do good work in keeping the peace, but they are not foolproof and there are occasions when the hotheads – some of them paramilitary, some of them aggro-seeking youngsters, spill on to the streets.
Yesterday police firmly attributed blame to loyalist extremists, who for a while have been largely inactive but who periodically flex their muscles. There may be more nights of rioting but, thankfully, there is no widespread appetite for trouble: there is instead a strong feeling that an isolated incident should not become general.