It's easy to blame PSNI for riots, but politicians share blame
Mr Justice Treacy delivered a damning judgment on the reaction of the PSNI to flags protests in the winter of 2012-13.
But the PSNI shouldn't have been the only people in the dock – the period also marked a failure of political leadership from which we have still not recovered.
First for the PSNI. The police lost control early on, misinterpreting the law and believing that, if people took to the streets without applying for permission to do so, then the police were legally powerless to stop them. This was self-evident nonsense.
It was, as the judge put it, "plainly inimical to the will of parliament" that regulations could be got around by simply ignoring them.
As Jamie Bryson – one of the leading protesters – put it, many of those involved in the protests believed that, if the police facilitated their activity, it must be legal. I remember Mr Bryson making the same point to me at the time.
The police may have felt that they lacked the resources to stop the weekly marches. Chief Constable Matt Baggott controlled fewer resources than any of his predecessors.
Police numbers were lower, he had no recourse to military back-up, and arrangements for mutual aid from British forces, which came into play at the G8 summit later in the year, were still not in place. That shouldn't have stopped the police warning protesters that they were breaking the law and would face penalties, even if, for operational reasons, there was sometimes a delay before action was taken.
High-profile protesters, like Mr Bryson and Willie Frazer, were not arrested until the end of February and, as Mr Baggott pointed out, more than 700 arrests were eventually made.
When this happened, the protests started to die down and protesters began complying with police decisions. Mr Bryson argued that "it is important to note that, once the PSNI definitively came out and said the weekly walks were illegal, the protesters desisted".
That was the policing mistake. It must also be remembered that nationalists pushed the flags issue without reaching agreement and some unionist politicians then tried to ride the tiger of the flag protests.
Instead of calming fears, they distributed 40,000 leaflets highlighting the issue and inflaming feeling.
Later, as this year's Peace Monitoring Report pointed out, the problem was that nobody was prepared to pick up the tab, or take responsibility, for the rising tide of sectarianism and disorder.
"Failure in Northern Ireland comes cost-free," it stated. "When the policing costs for contested marches and events spiral into millions, the organisers never receive a bill. The disconnect between the gathering and spending of taxes means no one feels responsible."
The report pointed out that last year's marching season cost £18.5m in additional policing costs, compared with £4.1m in 2012. It added: "Devolution, which was supposed to bring responsibility closer to local level, has failed to do so in Northern Ireland."
There were also protests from politicians when the police did start to make arrests and the courts began to remand people into custody.
Lessons have got to be learnt. When trouble flares up, it is the duty of governing parties to try to sort it out in the interests of all citizens and taxpayers, not to nail their colours to the mast in a partisan way.
This time, Assistant Chief Constable Will Kerr and the PSNI got the brunt of Mr Justice Treacy's criticism.
It is a pity the judgment did not give him scope to comment on the wider context against which the whole mess unfolded.