John Bercow blew the whole thing apart. After years of petty sneers and active sabotages of parliament by the government, he finally took his revenge. And it was huge: dramatic, constitutionally-explosive and with far-reaching repercussions for Brexit and British democracy. Once he was done, the prime minister's strategy was in ruins.
This was a long time coming. The referendum had created a new kind of sovereignty in British democracy. Since the English civil war in the 1600s, sovereignty lay with parliament, which gained its legitimacy through the elections held by the public. But the referendum result created a new form of political legitimacy: that of direct democracy.
Theresa May used this every chance she got. She portrayed herself as the sole custodian of the people's will. What that will actually entailed changed almost daily. Once upon a time it opposed any transition. Now it supports both transition and an extension of Article 50. But this is what authoritarians always do when they mention the will of the people: they conflate it with their own.
With this political legitimacy behind her, she abused and ignored parliament. She tried to deny it a vote on triggering Article 50. She tried to rob it of any meaningful say on her deal. She stuffed the withdrawal bill full of statutory instruments allowing ministers to operate as mini-parliaments. She tried to block amendments to no-deal announcements. Instead of risking losing opposition day motions, she simply pretended they didn't exist and refused to participate in them. She ruled-out publishing government legal advice on the backstop and then, when parliament demanded she do so, tried to ignore it. She was found in contempt of parliament - a historic humiliation which in any other period would have triggered a prime ministerial resignation. She set a date for a vote on her deal, wasted days of parliamentary time debating it, then cancelled it when she thought she would lose. After that, she held it, was defeated, held it again, and was defeated once more. And then she decided she would have another go this week.
Throughout that process, the Speaker had urged her to treat parliament with more respect. He made the point time after time, especially when she delayed the vote on her deal. In return, government ministers accused him of being a double-agent for Remain. "He's made his views known on Brexit," leader of the House Andrea Leadsom said late last year. "It's a matter for him but nevertheless it's a challenge and all colleagues need to form their own view of that."
But today, as May was holding last-minute talks in a bid to get the DUP on side, Bercow kicked back. And he kicked back hard.
There is a section on page 397 of the parliamentary rule book Erskine May which states that "a motion or an amendment which is the same, in substance, as a question which has been decided during a session may not be brought forward again during that same session".
Speaking to constitutional experts this morning, not a single one predicted he would go down this route. Most thought that the rule allowed for a very wide interpretation of what the "substance" of the motion was. For instance, it was not just about whether the deal had changed. It would also consist, in the words of David Natzler, the clerk of the House, of the "underlying reality" of the situation. So if, through conversations with MPs, Bercow thought there was a shift of support towards the deal - and the weekend newspaper reports suggested there might be - he should allow another vote as the "substance" of the matter had changed.
Not so. Instead he blew the lid off the whole thing. "If the government wishes to bring forward a new proposition that is neither the same nor substantially the same" as last week's, he said, that would be in order. But "what the government cannot properly do is re-submit to the House the same proposition or substantially the same proposition as that which was rejected last week".
May had been allowed to hold her second vote because she had secured changes to it in the form of the joint interpretative instrument with the EU and a joint statement. But this time she hadn't even pretended to enter into talks with Brussels. The deal was the same. And therefore so was the motion. And therefore it was against the rules.
Bercow's analysis of what constituted the "substance" of a motion was much narrower than expected. The idea of a shift of MPs towards the deal clearly had no impact on him. And neither did he care much if the attorney general could be persuaded to say something new about the Vienna convention or the way the backstop operated. His test was whether something had changed in the deal itself.
That was pulverising. It destroyed the government's strategy. All May's parliamentary chickens had come home to roost. Her constant disrespect towards parliament, her attempts to bully it into submission, had triggered a counter-attack from the Speaker at the worst possible time. There is now basically no chance for her to hold another vote this week.
Westminster fell into chaos once again. And then, as the dust cleared, we were able to get a little more clarity on the options open to the prime minister.
The first - and Bercow heavily hinted that this was the best course of action - was for May to go the European Council meeting this week and secure changes.
There are two types available. Firstly, she can try and change the future relationship document - the non-legal part of the deal concerning the ultimate arrangements between the UK and EU. Brussels is willing to play with that part, although admittedly probably not to this timetable.
Secondly - and this will be far more tempting - she can ask for a two-option extension of Article 50, as per her motion last week. Option one is for a short technical extension if she gets her deal through parliament before March 29th. Option two is for a much longer extension of perhaps a year if she doesn't. She should, by virtue of having secured those extensions, be able to present her deal as substantially changed. But there is no certainty that the EU is prepared to allow a two-option extension.
There are other strategies. She can try to pass a motion on her deal which starts "notwithstanding the practice of the House" on repeat motions. This would allow her to get rid of the rule for this one endeavour. But the trouble here is that she would need a majority of MPs to support it and it is not clear that she could secure it. Several hardline Brexiter MPs were supporting Bercow on this today. Presumably many moderate Tory rebels would too. And Labour and other opposition parties would whip against it
She could try and skip the motion altogether and simply put forward her withdrawal bill, which would turn it into law. That would then act as the de-facto motion on whether the Commons backed her deal. But this is a very unwieldy way to proceed.
And finally there is the nuclear option, where she would basically switch parliament off and on again. This would involve crashing the session and putting forward a new Queen's Speech. That is dramatic and could have very far-reaching consequences. Some even think it could end up dragging the Queen into the dispute. May will be loath to try it and anyway probably cannot do so before March 29th.
Those are the options available to her. By far the easiest is to hope that an extension arrangement linked to the deal is a substantial enough change for Bercow to allow it. But it is now clear that, whatever she does, the Speaker is prepared to go way out on a limb to obstruct her if he disapproves. Her room to manouvre just significantly narrowed. And the extraordinary constitutional battle between the executive and parliament just reached a new and dramatic stage.
"She only has to win once," SNP Westminster leader Ian Blackford warned the Commons last week. "We have to win every time."
That is how it feels. The prime minister can seemingly keep on putting down her Brexit deal, over and over again, hoping that at some point she wins it. And anytime she does, it is game over. She seems to be using a constant series of votes to bludgeon the Commons into submission.
But there is a limit to how often she can do this. Because this is British politics, it's not a simple limit. It's not a set number based on clear rules. It is an archaic system based on constitutional convention and political reality. But it does exist. And it does provide a kind of brake on the government.
Opponents of the prime minister thought they'd found an Achilles Heel to her strategy buried away on page 397 of the parliamentary rule book Erskine May. "A motion or an amendment which is the same, in substance, as a question which has been decided during a session may not be brought forward again during that same session," it read. "Whether the second motion is substantively the same as the first is a matter for [the Speaker]."
This wasn't a problem for the second meaningful vote, which was held last Tuesday, because specific changes had been made since Theresa May first brought it forward. In truth, they didn't add up to much, but on a basic constitutional level, the deal had changed. It had a new 'joint interpretative instrument', a joint statement and a unilateral declaration added to it.
But this time is different. The government is not even pretending it is holding new talks with Brussels on the deal. So the third meaningful vote May wants to put down is on a deal which is "substantively the same" as last week's vote. That seemed to give the Speaker, John Bercow, the right to intervene.
Clearly he was considering it. Labour backbencher Angela Eagle asked him if it was in order to keep bringing the vote back. "No answer is required now," he replied, "but a ruling will be made about that matter at the appropriate time."
But there's a problem. The rule is less water-tight than it appears at first glance. For a start, it is quite easy for May to claim she has changed the 'substance' of the motion. She can get the attorney general to add little thoughts on the applicability of the Vienna Convention, for instance. How convincing these thoughts are is another matter. All that really counts is that it allows her to claim that MPs are voting on something new.
After a while however, the Speaker could conclude this is just the government being clever and that the changes are superficial. That could then authorise him to intervene. However, there is a much greater test of his ability to block the vote. It is a key litmus test of pretty much every action he takes: the will of the House.
Last October, David Natzler, clerk of the House, appeared in front of a committee of MPs and was asked a series of questions about precisely this eventuality. Could the government just keep on bringing back the deal? He conceded that the Erskine May rule existed, but argued that the Speaker was limited in how he could legitimately enforce it.
"That rule is not designed to obstruct the will of the House," he said. "If it plainly was the will of the House, there are ways in which that could happen."
How? Natzler's answer was interesting. He said that the actual text of the motion could remain exactly the same, but the "underlying reality" could change. He went on: "The chair is there to facilitate the business of the House, not to operate a series of strange theological rules. They are there for a purpose, and it is the purpose that has to be looked at."
So how would the "underlying reality" change? The most obvious way is if lots of votes shift in favour of May' deal. That is an implicit demonstration that the will of the House is for another vote. This seems to have been the case over the weekend, with various newspaper reports of previous anti-deal Brexiters now saying they would support it.
However, there is clearly also a danger here. If May brings the deal back and the numbers end up not changing very much, there is a strengthened case for the Speaker to bar it from being put a fourth time. After all, the text won't have changed, and the votes won't have changed either.
This could be why the government is this week suddenly looking rather nervous about trying to hold another meaningful vote unless they are sure they will win. May knows that if these votes don't show real movement, they start to authorise the Speaker's intervention.
They also have another unrelated political effect: Every lost vote on her deal diminishes the prime minister's authority. She has now lost two. By the time of a third loss, Labour is likely to push another vote of no-confidence. And this time, she may win less support from her own MPs. Last week, hardline Brexiter Tory MP Christopher Chope was asked by a Labour opponent if he would vote for a motion of no-confidence in the prime minister. "Frankly, I would seriously consider that issue," he replied. This fact - more than anything on page 397 of Erskine May - could be what really influences her.
However, May does have another way of shaking things up - even if the text of the deal does not change and the votes in support of it do not shift. At the end of this week there is a European Council meeting. If no deal has been passed by then, No.10 says it intends to go to that meeting and ask for a long extension of Article 50.
This would then again constitute a change of the "underlying reality". Downing Street could return from that meeting hoping that it has made Brexiters' worst fears come true - and then try for another meaningful vote, using the Council decision as justification.
That's the game we're in now. There are lots of moving parts, from constitutional rules, to MP behaviour, to European positions, to assessments about prime ministerial authority. And what's worse, they are all operating in their own right while simultaneously having an effect on each other - dictating behaviour and then justifying it, in a horrible cycle of political machination.
Downing Street is trying to use every available lever to get its deal passed. And it does have a lot of ammunition to do so. But each time it goes for a vote, it uses up a bullet. They're sacrificed either in reduction of political authority, or by potentially providing evidence to justify an intervention by the Speaker. Either way, there are only a limited number of bullets left.
Ian Dunt is editor of Politics.co.uk and the author of Brexit: What The Hell Happens Now?
The opinions in Politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.
"It is time for this House to act in the national interest," Brexit secretary Stephen Barclay said last night. "It's time to put forward an extension that is realistic. I commend the motion put forward by the government to the House." And then, minutes later, he went into the No lobby and voted against it.
The extent of the hypocrisy only grows when you look at the rest of the speech he made. His very first sentence praised the "integrity" of Keir Starmer's support for a second referendum. He then recognised the "sincerity" of Chris Leslie for leaving his party to join The Independent Group over Brexit. After that, he criticised Jeremy Corbyn's lack of "principle or integrity". And the entire time he was making a speech in defence of a proposition he was about to vote against. At some point he must have written those lines, knowing what he was about to argue for and how he would behave after doing so.
He wasn't alone. Several other Cabinet ministers voted against an extension of Article 50 last night, including Liam Fox, Chris Grayling, Andrea Leadsom, Penny Mordaunt, Liz Truss and Gavin Williamson. It was a free vote, so there was no consequence to this, except as an exhibition of how battered and ruined the government is. It simply cannot maintain any discipline.
Without opposition party support, the government couldn't have gotten the motion through extending Article 50, and we would right now be committed to no-deal. That is effectively the stated will of the Conservative party. It has turned into a millennialist death cult.
Or perhaps it hasn't. Who knows? MPs' votes have become so divorced from what they claim to believe that it is hard to tell what's going on anymore. Many would have voted differently last night if the question was about conviction. But it was not. They knew they could get away with it. They knew that more responsible minds than their own would vote for extension, so they could confidently vote against and not face the anger of their increasingly deranged echo-chamber local association. The same applies to Theresa May's deal. Lots of MPs have no issue with it. A great many of those opposing it want it to pass. They just can't be seen to be supporting it.
That political psychosis is not restricted to the Brexit side. Labour's official policy, if indeed it can be said to even have official policies anymore, is to support a second referendum. But last night it demanded its MPs abstain on an amendment demanding precisely that.
At least that reflects the conflicting wishes of the parliamentary Labour party, which has several figures implacably opposed to another vote and others intent on supporting it. The People's Vote campaign has no such excuses. The clue to its purpose is in its name. Just next weekend, it is helping to organise a march through central London to demand a People's Vote, but last night it was trying to get MPs to abstain from supporting the very proposition it was set up to secure.
The reason stems from deep-seated tactical disputes within Remain. The People's Vote camp behaves like Labour used to behave towards the Liberal Democrats: with a sense of outrage that anyone else dare portray themselves as representing a critical movement on Brexit. This has led them to regular attacks on the Norway option, because it can present itself as an alternative to the People's Vote. By doing so, they have savaged their own back-up option and the very model Brexit critics will have to support if Britain does leave the EU. This last-man-standing approach means they refuse to put a second referendum before parliament until they are sure it will pass. And that insistence, which has become totally inflexible no matter how things develop, now sees them demand abstention on their core principles.
When the results came in for the vote, Jacob Rees-Mogg tweeted: "A second referendum, the so called 'losers’ vote', has now been defeated in the House of Commons so is it is off the table."
His previous tweet read: "The law still says we leave on 29th March." This was sent after no-deal was defeated in the House of Commons. The hypocrisy and brazen self-interest is now so severe that you do not even need to scroll down people's Twitter feeds. You can track it from one message to the next.
The poison of meaninglessness and failure of conviction is everywhere. Last night, Brexiters who campaigned to leave the EU on the basis of returning sovereignty to parliament voted against an amendment by Hilary Benn which would have given parliament control over the process. On Wednesday, the government whipped against its own motion on no-deal, suggesting that it held the precise opposite view to the one it is committed to. Earlier in the week, Nigel Farage, who presents himself as a British patriot fighting against foreign interference in our sovereignty, lobbied far-right European leaders to veto a British petition for Article 50 extension authorised by the Westminster parliament.
It is madness, on a system-wide level. Principles have crumbled to nothing. All that's left is transitory tactical interest, fossilised strategic assessments, and the perpetual trembling terror of MPs in the face of the referendum result and zealots in their local associations.
Many of the arguments against a People's Vote rely on warnings about damage to public trust in politics. But the spectacle of hypocrisy we're being treated to right now does that more effectively than a hundred referendums ever could.