How do you negotiate with people who can’t agree on anything? Even a brief look at the state of the wider EU should be enough to illustrate the practical problems facing David Cameron in his attempts to redraw Britain’s relationship.

Take this week’s summit. Even before they got onto “the British question”, the leaders were in disarray. What to do about Greece? Don’t know, let’s keep fudging it at vast monetary, economic and human cost. How about the migration crisis? Well, there are all sorts of different proposals so let’s pick none of them, at vast monetary and human cost.

This total indecision is, of course, a symptom of the EU’s fundamental failings. There is no demos, no shared worldview, values or objectives to allow the various member states to even start addressing problems, never mind approaching settling on solutions.

Given that setting, it’s impossible to see how the same divided, decision-averse group could ever really get to grips with the detail of a meaningful renegotiation of Britain’s membership. And that’s before you take into account the fact that the Union itself is ideologically and structurally opposed to the idea of any loosening of the ties that bind us all in to the project.

All of which helps to explain why the Prime Minister has now conceded that treaty change will not be achievable before the in/out referendum. Instead, he says, he will seek an “irreversible lock” to guarantee any deal will be lasting.

Unfortunately for him, the only kind of “irreversible lock” mechanism that works on EU matters is, er, treaty change. When people suggest that eurosceptics see such change as a goal in itself they are either mistaken or deliberately misleading – the treaties only matter because they are the supreme authority for how the EU functions. Unless any new relationship is written into the treaties, the EU courts will simply erode it by continuing to make judgements on the basis of what the treaties still say. In short, any such deal wouldn’t be subject to a lock and it would be reversible.

Cameron himself recognised this earlier in the year when he said the reforms he seeks (relatively modest though they are) “do involve treaty change, and proper, full-on treaty change”. The end to ever-closer union, the redrawing of rules on migrants’ access to welfare, increased power for national parliaments to block bad decisions from Brussels – all these and more require the treaties to be redrawn. The about-turn on that line is not due to an unforeseen demand, or the timetable he set himself – it is due to the fundamental nature of the EU itself.

Inherently opposed to loosening its grip on power, fundamentally divided even on issues that don’t involve devolving power back to member states and ultimately incapable of agreeing on its own future, the EU may eventually find enough papier maché and sticky-backed plastic to cobble together a deal of some sort for Cameron to bring home – but all the signs are that it won’t live up even to his initial demands, and even then it won’t be binding. Which leaves Out as the only option.

The sorry state of affairs can be seen in the draft communiqué issued by the European Council following this week’s meeting. It doesn’t even mention the word renegotiation, but it does give two sentences to the troublesome Brits:

“The UK Prime Minister set out his plans for an (in/out) referendum in the UK. The European Council agreed to revert to the matter in December.”

And that’s it. Moving swiftly on, the next item announces that Jacques Delors has been granted the title “Honorary Citizen of Europe”. It seems that such ephemera are all that the organisation can agree on these days.