An appalling sense of déjà-vu is sweeping Belfast, causing its people to contemplate not just the awful mess caused by rioting but an even more awful thought: Is this city fated never to know real peace?
The Troubles were supposed to be on their last legs, drawing slowly but surely to a close. Life has improved hugely in a decade, and violent death is far less common than it was. The volcano was supposed to be dormant. Things were supposed to be settling down, not erupting with such suddenness and such force. Belfast was supposed to be a modern city, not one so volatile that a single banned Orange Order parade could create mayhem.
When the Orange march was banned from a nationalist district, the boys were called out. That meant the youths from loyalist areas, but in Belfast the word "boys" still retains the Shakespearean sense of armed men. They came out as well.
Loyalist paramilitary groups such as the Ulster Volunteer Force are free-standing entities within Protestant communities. But they do have political radar: the head of the UVF, for example, has been shrewd enough to hold that post for 25 years.
As well as hearing what the Orange Order said, he heard what Unionist politicians did not say: there was little in the way of heartfelt, unequivocal appeals for calm.
The US administration and others have criticised Unionist and Orange figures for their performance, and indeed, it was not long before incendiary statements and gestures were followed by actual incendiaries.
A click of the paramilitary fingers was all it took to bring tattooed loyalist ex-prisoners scrambling out of the paramilitary pubs and on to the streets, pausing only to manufacture a few crates of petrol bombs.
Being told to get stuck in is not an imposition for these tough guys - instead, they tend to view it as a pleasurable duty. Getting stuck in involved injuring 50 police officers and causing millions of pounds of damage.
The orgy of careless destruction has been mostly within loyalist areas, making already rundown districts even more wretched, but the rioters do not fret about the damage.
They do not care. In the mornings in east Belfast, men - including some rioters - are to be seen standing cheerfully in the sunshine, watching council workmen clear up the mess from the night before. The fact that they have defaced their own district simply does not register with them.
The decline of the Troubles has reduced the size of their organisations but they are still in being and are still up for occasional bouts of bother. This is partly because that is the kind of people they are, and partly because of general underlying loyalist alienation.
The peace process has brought huge benefits to Belfast, but ask anybody in a loyalist area and they will say: the other side gets everything, we get nothing, nobody listens to us, they only thing they pay attention to is violence.
They say the government is putting terrorists in government, appeasing the IRA, weakening the union, running down security. The irony is that the rioting is coming from within a community which cries out for law and order, which opposes a military rundown, whose catchwords are stability and security.
Yet many of its teenagers are out on the streets at nights throwing petrol-bombs and blast-bombs at police Land Rovers, jeering and whooping with delight when a vehicle bursts into flame.
Loyalist dads sit in their homes saying the government should not reduce the military presence in Northern Ireland any further. Loyalist kids are meanwhile outside flinging petrol bombs at troops.
It matters not that the police - who are mainly Protestant - are taking a battering, as indeed is Northern Ireland's economy, its slowly improving image, its overall sense of morale and its hope for a better future.
Loyalists used to call Catholics and nationalists whingers, saying they were always complaining and never satisfied. Now it is loyalists who feel they are the new second-class citizens, who are full of angst and bitterness.
The role reversal is almost complete: now Catholics have confidence, high expectations, and well-developed political skills. Now loyalists are disgruntled, disheartened underdogs with no faith in their politicians and no confidence in their government.
The sight of hardline Protestants expressing their insecurities by attacking the security forces is nothing new. It has been happening for so long, a couple of hundred years, that any sense of paradox or incongruity has long since gone. It is, rather, the resort of the chronically inarticulate. The issue of the Orange march was simply the last straw for many parts of loyalism, a brutal, ugly cri de coeur from people who feel friendless, leaderless and out of sorts with the world.