On the whole I imagine that policemen are more used to breaking up rows than being the cause of them. But in the case of the fundamental changes to policing in England and Wales being proposed by the Home Office, that's exactly what they are.
Imagine I'm a traffic police officer - here's a quick recap on where we've been, where we are, and where we may be going.
Where have we come from?
The UK Government wants to introduce elected police commissioners in England and Wales. Policing is not devolved, so it can do this.
It also wants to change the scrutiny arrangements though, abolishing police authorities - which it can do.
It wants to replace them with Police and Crime Panels, which would be set up as committees of local councils. And this is where it's run into a problem.
Only the National Assembly can pass legislation relating to this aspect of local government in Wales.
Fortunately, there's a mechanism called a Legislative Consent Motion - LCM - cousin of the LCO - where the Assembly gives its permission for Parliament to step onto its land. In effect it gives its permission to temporarily transfer legislative powers back from Cardiff Bay to Westminster and pass a law in that area on its behalf.
There have been a number of these LCMs since 2007, all of which have passed through the Assembly utterly uneventfully.
The Assembly Government is opposed to the introduction of elected police commissioners in Wales. In a series of meetings stretching back to last autumn, the Social Justice Minister Carl Sargeant pushed Policing Minister Nick Herbert to allow Wales a complete opt-out from the system - to keep the status quo here.
Nice try, said Mr Herbert - but policing responsibility is England and Wales and that's the way I'm going to go.
Up to you then, said Mr Sargeant. But I hope the Assembly passes the LCM so you can have your Police Panels here. And since I disagree with the policy - as do my colleagues in Plaid Cymru - don't expect me to bend over backwards to push it through, even with concessions around the Assembly Government's rights to appoint a couple of people to each panel.
Mr Herbert saw which way the wind was blowing and wrote to all AMs on Monday warning them that turning down the LCM would be "a hollow victory". Hollow or not, Plaid and Labour backbenchers voted against, their ministers abstained, and the Lib Dems and Tories voted for. Result - no consent.
So where do we go from here?
There appear to be two different views - one at each end of the M4. The Home Office and the Wales Office are playing it down, saying not only will Commissioners go ahead but the Panels will too - and all that will happen, in fact, is that the concessions offered to Carl Sargeant will be withdrawn. Hence Mr Herbert called the AMs "unwise" and accused them of "cutting off their nose to spite their face".
Others, including the Assembly's Presiding Officer Lord Elis Thomas and his advisers, say the situation is much more serious.
The Assembly has legislative competence over local government, and specifically over scrutiny committees formed out of local councils (Matter 12.7 of Schedule 5 of the Government of Wales Act if you have it there on your shelf). The Presiding Officer's clear and forthright view is that it would be unconstitutional for the Westminster government to press ahead and legislate for Police and Crime Panels in Wales, since powers over this are held in Cardiff not in London.
In exactly the same way that the Assembly would be acting illegally if it tried to legislate on things that it doesn't have powers over, now for the first time, the boot is on the other foot, so to speak.
And it must, at least, be worth noting that this view seems to be given some added weight by the amount of lobbying done by the Home Office and the Wales Office over this LCM. If they are quite certain that it only refers to the concessions, not to the Panels, why bother going to such lengths to persuade the government to back it and AMs to vote in favour of it?
At the time of writing, the Home Office and the Wales Office are sticking to their guns.
We shall see.