Somewhere in Whitehall, there’s a small office. In it, a bright young thing is working hard on Brexit. As the afternoon sun bounces down to the tiny window that provides the only fresh air, a spark flares up in the bright young thing’s mind. They dash down the corridor to their line manager, bursting through the door to breathlessly stutter: “I… I think I’ve solved how to do it.”

This, to a not inconsiderable extent, presents how many in government would have liked things to go over the past two years: a model to solve all the problems and leave everyone stunned by its beauty and creativity: Britain is GREAT at cunning plans, indeed.

Sadly, things haven’t quite worked out like this.

The breadth and depth of the issues involved, plus the rather arbitrary red lines that May set out upon her entry into Number 10, have made both simple and cunning solutions impossible. The best our imagined bright young thing might come up with is that something’s got to give.

In fairness to the government, this last point has been evident for quite some time: the difficulty has been in deciding what should give and how that’s going to be broken to all involved.

Neither of these are easy, even before we add in the obvious political and reputational costs that would be incurred. In the very worst case, the government might make a concession that leads to its demise as a viable political unit: leadership contests, party splits, general elections, ‘out of power for a generation’, etc., etc.

But at the same time there is also the ever-stronger conviction that to leave the EU without a deal would be an unnecessary and deeply counter-productive move: the ‘freedom’ it might generate would be lost in the miasma of uncertainty and damage to the UK’s standing in the international community. As the on-going discussion about an FTA with the US underlines, the UK is very much a demandeur: its need to show it can still get deals means everyone else can set a high price. Domestically, there’s also plenty to worry about as it is, even if things do run smoothly.

So let’s play the game for a bit: what does the UK have to give way on?

The big one is the balance between alignment, territorial integrity and the Irish border. If the ability to diverge matters more, then the backstop looks the least painful way to do that. The DUP won’t be happy, but if Labour get on board with the package, then it doesn’t matter (in Commons arithmetic terms, at least). If diverging isn’t so important – and remember there’s a difference between diverging and having the potential to diverge – then full UK alignment on backstop terms might work, And if neither of those work, then the UK government needs to get ready for a no deal outcome.

The smaller issue is the role of the Court: it matters, but less so, not least because technical work-arounds look more viable (mainly because they’ve already been tired out elsewhere). But essentially it requires the UK to give way on its very literal interpretation of this red line, which was never realistic in any case (as government lawyers doubtless pointed out at the time).

The cover for all this is some kind of ‘temporary‘ arrangement: witness the by-the-by noting that given the current inability to go either the customs partnership or maximum facilitation, we might just have to live with a decade or so of full alignment: lift your eyes from the mud to look at our bright, bold future.

At some level this makes sense: if people are willing to accept that this is a complex change and takes time to do properly, then the deferral might be worth it. However, if they consider it to be another step down the road of endless delay, then it’s not going to work.

Of course, much hangs on which ‘people’ we’re talking about.

In essence it’s the Tory backbench that matters here. Cabinet has its splits, but the agency of any faction to impress its preferences depends on the 1922 Committee and the ERG. Likewise, a determined backbench can stymie any attempt to reach across the aisle by prompting leadership challenges.

As I’ve noted before, the backbench isn’t minded to crash the Brexit bus, but that doesn’t mean it won’t exert a good deal of pressure on May and the Cabinet’s work over the coming months. Any putative challenger needs the cover of a conclusion of a deal before moving in, so might feel that concessions are acceptable, especially if it allows them to strengthen their case that they would have done a better job, if only they’d been in charge at the time.

However, as so often in this process, nothing is really certain. Individuals might prove inflexible, by design or by accident. Events might conspire to deny enough room for manoeuvre. The EU might succumb to hubris and overplay its hand.

Pretty much the only thing that’s clear is that the rest of 2018 are not going to be easy going for anyone involved in this. A bright young thing might decide to just keep their head down, rather than get stuck in: that might make sense for them, but not for the process as a whole.