Sinn Fein had some prospect of holding the high ground over the reporting of the incident in which Gerry Kelly was carried on the bonnet of a police Land Rover.
The police themselves were staying out of the argument.
And Culture Minister Caral Ni Chuilin's injuries might have attracted sympathy and reinforced the perspective that two diligent MLAs, working overtime to bring peace to their community, had been brushed aside in a show of brute strength by a police driver.
Then Sinn Fein issued a video of the whole incident. And from that it is easy to read what was going on and to attribute the balance of blame.
And while Kelly is left with the argument that a driver should not proceed against a protester standing directly in his path, it is plain that he should have had more sense than to be there.
Not just the sense to avoid danger, which Gerry Kelly has never had, but the sense to understand his own responsibilities as an elected representative and a member of the Policing Board.
He had approached a line of police vehicles in the company of the mother of a young man who had been arrested.
He had demanded the right to speak to the officers in the vehicle. And he had understood that they had agreed to give him a hearing. On that basis, he urged the crowd around the vehicle to stand back, assuring them that the driver was going to pull in round the corner.
But the driver made off, and Kelly tried the vehicle behind him, which also refused to stop for him.
Now, rather than let the crowd see that he could not order the police to stop and talk to him, he stood directly in front of a Land Rover. Then he barked his orders at the driver: "Pull in!"
But the driver turned on his alarm lights and siren and inched forward, presumably expecting to brush Kelly aside. Kelly, perhaps terrified, clung to the grille on the bonnet of the vehicle, and six seconds later it stopped, now with a raging mob yelling at the officers and thumping the side of it, believing the arrested boy to be inside, which he wasn't.
What then followed was a berating of the police by Gerry Kelly, roaring his complaint at a senior officer and demanding the identification of the driver of the vehicle – and getting it.
What is shocking about this is that Gerry Kelly had no reservations about issuing orders to police personnel on duty; that the senior officer expressed no complaint about Kelly's behaviour, presumably having long understood the need for judicious docility in such situations; and that Gerry Kelly isn't one wee bit ashamed of himself, and hasn't shown the slightest notion that there was anything untoward in what he did.
He sees no contradiction between his presumption of the right to bark at the police and the legacy of opposition to political policing.
He would be the first to complain if anyone else tried to interfere with the police in the same way, but he lives in the apparent confidence that he has authority to demand that the police bend to his will. What is even more amazing is that, in making a show of himself like this, he has actually upstaged the story his party wanted told, of how the Tour of the North parade behaved passing St Patrick's Church.
But he isn't the only one who has lost his political touch.
The party itself, in releasing the video, has provided the evidence which damns him.
And Sinn Fein used to be such good propagandists.