In a sense, today was a moment of victory for Brexiters in government. They have managed to kick the can a little further down the road. But this merely delays the inevitable and raises the stakes. The crisis did not come now, so it will come later. But it will come. Autumn is going to be a very intense and potentially catastrophic period in British politics.
Everything hinges on the Irish question: How do you maintain an open border when you want to have different tariffs and different regulations?
The EU could have forced the Irish issue at the first phase of the talks in December. They didn't. They said Britain could find a solution via it's trade agreements with the EU (staying in the single market and customs union) or it could find a technical solution (sci-fi nonsense which will never happen). If both those things failed, there would be "regulatory alignment" between North and South Ireland. This would mean that either the rest of the UK went into regulatory alignment with the EU, or Northern Ireland was carved out as a distinct economic space. The first option is not acceptable to hard Brexiters and the second is not acceptable to the DUP, or the Tories, or Labour for that matter.
The EU could have also forced the issue today. But it didn't. It has agreed on the transition and talks should now be able to move onto future trade in April. This seems like a major Brexit victory, but it is in a truth a relatively minor one. Nothing has changed. A ball of impossibility sits there in the middle of the Brexit process and they just keep on kicking it down the road. But what happens when you run out of road?
The quid-pro-quo of allowing talks to move on is that the legal text of December's three-stage deal on Ireland has been included in the withdrawal agreement. This is significant.
It ignores the first and second stages and looks just at that regulatory alignment third stage - now termed the 'backstop'. And it really is laid out in brutal detail.
The report reminds the UK that it is committed to "avoiding a hard border, including any physical infrastructure or related checks and controls" and that "any future arrangements must be compatible with these overarching requirements". It states that the agreement "is based on the third scenario of maintaining full alignment with those rules of the Union's internal market and the customs union". And then it lays out what that means, in language which would horrify any Brexiter:
"A common regulatory area comprising the Union and the United Kingdom in respect of Northern Ireland is hereby established. The common regulatory area shall constitute an area without internal borders in which the free movement of goods is ensured and North-South cooperation protected in accordance with this chapter."
The document is colour coded green, yellow and white, with the white sections indicating where "discussions are ongoing as no agreement has yet been found". It goes without saying that this section is in white.
So what does this all mean? In a way, not much. The EU has allowed talks to move ahead, but there is a section of the document which simply cannot be solved. The government is not going to agree to carve out Northern Ireland as a separate economic territory. And it is unlikely to keep the rest of the UK in the single market and customs union either. So the border cannot be around the UK, or in the Irish Sea, which means it has to be across Ireland. Except that it can't be, because the UK has said that won't happen. What the UK wants remains impossible.
So now we will have another few months of Brexiters pretending the problem can be solved. They will talk about technological solutions, about the US-Canada border and the Norway-Sweden border. But the truth is that even the most high-tech, untested, super-futuristic border will only minimise infrastructure, it will not eradicate it. And even that will take longer to install than December 2020, which is when transition supposedly ends. What they have promised cannot be delivered. And the backstop solution which activates if they fail to deliver is considered politically unacceptable. This is a riddle with no answer. It is a dog trying to catch its own tail.
Plenty of people on both sides of the debate will speak very confidently about what will happen now. They should be more modest. It is very hard to see how this will go. Despite the smiles on display today, Michel Barnier and David Davis are now engaged in a game of chicken. Either the UK will buckle. This means agreeing to stay in the single market and custom union or that Northern Ireland should do so. Or the EU will buckle and allow a deal to pass that creates a hard border in Ireland.
Overall, it is more likely that Davis buckles. As Barnier said today, "nothing is agreed until everything is agreed". That means that in autumn this year the UK would face the whole deal collapsing if it doesn't sign up to the backstop: no transition, no customs infrastructure, no regulatory infrastructure, no trade deal with the EU or roll-over of third party deals. Disaster. This dynamic suggests Davis will panic first.
But that isn't necessarily the case. The Brexiters are quite delusional enough to demand political and economic suicide. The political temperature is sufficiently high that anything is possible. And the EU, faced with the horrific reality of no-deal and a UK which has seemingly lost its mind, might still authorise some fudged nonsense into transition.
Today bought some more time, but the pressure continues to ratchet up. Ireland still sits there, like a black hole, in the centre of the talks. It is a spasm of chaos waiting to happen.
The week wasn't really defined by the Russian nerve agent attack. It was defined by the British response. The spotlight we'd expect to shine outward turned inwards and, in a way that's become depressingly common, we didn't like what we found.
Strip it down to its bare bones and you've got a relatively simple situation here. The evidence overwhelmingly points to Russian state involvement. They have the motivation, they have the ability and they have the track record. No-one else does. But it is not proven yet and in all likelihood, because of the nature of the operation, never will be. So there is enough doubt for conspiracy theories to blossom and nervy politicians to be frozen by inaction.
In normal times, the obvious story would have defeated the imaginative ones. But we are not living in normal times. We are living through a substantial breakdown of trust in government and media. So instead of presenting a united front, British politics fell into recrimination and division.
Jeremy Corbyn made several errors in his response to Theresa May's statement on the Salisbury attacks - some of judgement, others of tone. But the key element was his eagerness to find an alternate explanation for the incident.
His statements were confused and contradictory, probably due to a growing sense of crisis as his back and front benchers rebelled against him. On Thursday afternoon he agreed "all the evidence points towards" Russia, but by Friday morning he had written an article in the Guardian claiming "a connection to Russian mafia-like groups that have been allowed to gain a toehold in Britain cannot be excluded".
He is right, it cannot be excluded. But there seems little reason to think it is the case. The nature of the nerve agent makes it highly unlikely.
Novichok, the 'N-series' of nerve agents, was secretly developed in Russia in the 1970s. Most of the information we know about it comes from Russian chemist Vil Mirzayayanov, who exposed the programme in 1991. It acts by flooding the gaps between nerve cells with acetylcholine.
It's really powerful stuff. A drop of VX, from the V-series, can kill a healthy adult. But the later N-series is much stronger than that, especially in the form of the most potent members - Novichok-5 and 7.
That's why they are binary agents, made from two safe precursor chemicals which are then mixed together just before use, probably at a pesticide or fertiliser manufacturing plant. This allows an agent to transport the chemicals safely and only create the lethal mixture when absolutely necessary.
Why on earth would a Russian mafia want to do this, rather than just shoot someone? What possible criminal group would have the means of achieving this? And why?
The involvement of the Russian state answers both those questions. They have the ability. In fact, they are the only people who know how to produce the agent.
They have the motivation, which is to send two messages. The first is to Russian double-agents that they can track them down. The second is to the international community, and Britain in particular, that they can act indiscriminately in the sovereign territory of other states, while still being considered respectable enough to host major international sporting tournaments like the World Cup.
They have also exhibited the pattern of behaviour to make this scenario credible, not least in the murder of Alexander Litvinenko using a radioactive isotope in 2006. As Nato secretary-general Jens Stoltenberg told the BBC:
"We have no reason to doubt the findings and the assessments made by the British government, not least because this takes place against a backdrop of a pattern of reckless behaviour by Russia over many years. The illegal annexation of Crimea, the continued destabilisation of eastern Ukraine, cyber-attacks and meddling in national elections, and many other activities. This is one element of many."
To compare this case with the security dossiers on Iraq, as Corbyn's spokesman Seamus Milne did, is absurd. This is a specific incident, in a small location, on British soil, which can be tested domestically by world-class analysts. It is not the same as the inane reports compiled by a desperate administration to create an excuse for war on the military capacity of a state they had not visited.
But in one sense Milne is right. At the heart of this is Iraq and the body-blow it dealt to the country's trust in itself. Iraq was the first domino. It broke trust in government. The financial crisis broke trust in the economy. The expenses scandal broke trust in MPs. Phone-hacking broke trust in the press. The Jimmy Savile outrage broke trust in the BBC.
One by one, the institutions crumbled.
Since the Brexit vote, many people claim that economic arguments are not considered important by the public. In fact, polling suggests they remain highly pertinent. What changed is that the public did not believe those making economic warnings. The trust was gone.
Something similar is happening here. Most will be willing to go with the account given by No.10 and the overwhelming majority of experts. But for many others, there is enough uncertainty to create a different narrative. One of 'false flag' incidents, which are so popular on the internet among the deranged and the terminally ironic. Or one where the government is accused of carrying out the operation to distract from its other errors. Or one where you can argue that - who knows? - maybe the mafia did it.
This is the age of distrust. It goes from the bottom of the internet sewer to the office of the leader of the opposition. It makes firm, concerted action and national solidarity almost impossible.
We don't admit it, but there is something oddly reassuring about underhand Russian operations. They remind us of a simpler time, when there were good guys in the West, bad guys in the East, and the moral chaos of September 11th, fake news and the financial crisis were years in the future.
This week's extraordinary events, in which former spy Sergei Skripal and his daughter Yulia were attacked using some kind of nerve agent, even felt at times like an ITV drama. The fact it took place in the unlikely location of Salisbury, a tranquil and picturesque Wiltshire town, cemented that impression.
But the reality is quite different. If this is eventually proved to be a Russian assassination attempt it takes place in a bleak new reality, one in which the subversion of information is a core component of international conflict. It takes place in a Britain which is far less sure of itself and its place in the world than it was in the past.
The authorities have struggled to isolate the agent used or where the attack took place. It may have been slipped into Skripal's food or drink at the pizza restaurant he ate at, or in the pub he visited, or perhaps surreptitiously in a gift his daughter brought back from Russia, or it may have somehow taken place at home, or it could have been sprayed at his face by someone approaching him in the street. Without even quite basic information about what took place, we were left to follow logical conclusions - that a former Russian agent of the type Vladimir Putin is on record saying he'd like to get was attacked using a method previously adopted in Russian operations. But there was no firm proof to make water-tight what that reasoning led to.
Instead, the foreign secretary was left to go to the Commons and inform MPs of the situation. As usual with serious news events - think back to his behaviour during the London riots - the Boris Johnson brand of quibbling loose-lipped swagger proved highly ill-suited to the gravity of the situation. He managed to wrongly state that the England team would boycott the World Cup in Russia, only for his staff to later clarify that he meant dignitaries. He then seemed to suggest that this and other Russian efforts were an act of war - a comment which carries greater repercussions than he appeared aware of.
A pretty standard series of ideas for how to respond followed, including diplomatic expulsions and new financial sanctions. None of them seemed likely to scare the Kremlin. All of them have been tried before. There is little to suggest this would stop the Russians trying another similar attack. It certainly hasn't until now. Some reports suggest they may have carried out 14 other assassinations in the UK since the killing of Alexander Valterovich Litvinenko using a radioactive isotope in 2006.
The lack of ideas about how to respond to Russia is demonstrative of how unlike the Cold War this is, despite appearances to the contrary. The new conflict is not really conducted by big power blocks carrying out assassinations. It is conducted by information warfare, which intends not to convince an audience of something, but to make it impossible for the public, in any country, to really know what is true and what isn't - or even if truth exists.
The Russian programme involves trying to subvert the American and French presidential elections and - in all likelihood - to interfere in the Brexit referendum. It sees bots and troll farms seek to lather online debate into a fake consensus around political and cultural issues. It mangles reality.
This attack does not take place in a Britain which is sure of its international relations and the protection of its allies. Quite the opposite. It takes place as the full spectrum of British political and administrative attention is on Brexit, as it tries to untie its own bonds with its allies and the rule-based international order it helped create. It takes place as a volatile American president signals his complete lack of interest in Nato and a willingness to sabotage the WTO, either through aggressive tariff programmes or simply leaving it.
Britain is isolated and divided, during a confusing period of intense technological change which favours insurgent activity, and working amid a fraying international order which it is itself helping to undermine. The weird nostalgia of the Cold War which this case encourages couldn't be further from the truth.Things are much more dangerous now.