This election will be won or lost on a single question: what matters? What issue, at 6pm on Thursday 12 December, will be in the mind of a van driver who has just finished work as they go out into the darkness — which in northern England descends mid-afternoon — and queue to vote?

The Conservative gamble was that the issue would be Brexit: or more specifically “getting Brexit done”. They calculated that by actually achieving a deal, no matter how shabby, combined with the widespread crisis fatigue among voters, it would give them a chance of flipping enough Labour Leave voters to win a majority. The Tory electoral machine would squeeze the Brexit Party vote, while the salience of the Brexit issue itself would stop Labour squeezing the Lib Dem vote.

But the dramatic decision by Nigel Farage to stand candidates down in 317 Tory-held seats has changed the game. And it was clearly not a unilateral decision: Boris Johnson, behind the scenes, sent emissaries to plead with Farage to make this move, while the right-wing tabloids mounted a public campaign of pressure on all his candidates to stand down.

This, then, was a move by Johnson, not Farage. Experience on the doorsteps of marginal constituencies over the past two weeks suggests why he had to make it: the “decent Tory” vote is very soft. From Plymouth to Milton Keynes, when Labour canvassers meet in the pub to swap notes, a new tribe has been discovered: the person marked down as Tory on the voter ID list who is now “not sure” how they’re going to vote. Veterans at reading subtexts, activists interpret this as “fairly sure they’re going to vote Lib Dem” or “going to the local Winter Wonderland with the kids” instead of voting.

With the liberal conservative vote softening, Johnson’s strategists clearly understood the organic squeeze on Brexit Party voters was not enough; that something drastic had to happen. And getting Farage to stand down half his candidates is fairly drastic. To understand how this might change the dynamics of the next 29 days, you have to understand how it was supposed to play out.

In phase one, the Tories have been trying to otherise Labour, making its candidates out to be terrorists, thugs and anti-Semites, while focusing all minds on Brexit. That's why they have made almost no policy announcements and done very little stump campaigning.

Phase two begins with the manifestos: Labour's comes out next week, and will no doubt concretise the £400bn borrowing around specific spending plans. Following the adoption of more relaxed fiscal rules, it is likely to offer a “tax the rich” programme at least as big as 2017’s £49bn plan.

Since both main parties are throwing large figures around when it comes to spending, this second phase was always going to be about credibility. That's why Johnson is releasing the Conservative manifesto only two weeks before the election — limiting scrutiny in the hope that the fiscal policy shambles it contains will be ignored when the third and final phase starts.

Phase three is going to be a stage-managed elite panic over Corbyn. Forget the “Zinoviev letter”. If it looks like Labour has closed the polling gap on the Tories through relentless doorstep work and “organic social media”, there will be one Zinoviev letter per day in the run-up to the poll: ludicrous fake news stories amplified willingly by people who call themselves journalists.

It won't, of course, be MI5 doing the faking. We exist, for now, in a democracy ruled by law. But numerous external actors stand poised to help stop a progressive government and force through Brexit. Mike Pompeo, the US Secretary of State, said publicly in June that, if Corbyn’s election appeared likely, the US “won’t wait for him to do those things to begin to push back. We will do our level best.”

Seasoned observers of Kremlin propaganda, meanwhile, noted with interest an article by the news agency Sputnik headlined “Labour Party Suffering Drastic Loss Of Support”, which cherrypicked recent polling figures. The Russian-owned outlet has turned mildly but relentlessly negative against Corbyn since the election was called, for example repeating “intelligence community fears” that the Labour leader is a national security risk.

So that is the script. But with the emergence of a de facto Johnson-Farage pact, the script can be rewritten. What's been striking on the doorstep is how sensible ordinary British people are compared to politicians. In the political bubble, especially the one created by the BBC via the relentlessly histrionic Question Time and Politics Live, everything is cast as a life or death issue. Voters, by contrast, know that whoever wins, life will go on.

Communities are split over their reception of Labour canvassers — you can be hailed as a saviour and offered a mince pie at one door and denounced as a terrorist two doors down — but they are not at war with each other. In this atmosphere it is possible that, incrementally and with big regional variations, Labour can move the agenda on to health, tuition fees and police numbers.

Faced with the Tory fake news attack on its fiscal policies, Labour has weathered the storm and pushed back. The result is Sajid Javid’s refusal to agree to a TV debate with John McDonnell.

But while Labour has inched forward a few points in the polls, the self-inflicted squeeze on the Brexit Party vote is handing the Tories even bigger gains. And so, beyond Labour's control, a new and more rational panic will begin — among the clear majority of voters who want to stop Brexit. They understand that the Johnson-Farage pact signals the emergence of a new kind of conservatism, which is prepared to crash out of the transition period without a deal in 12 months’ time — and which holds our democratic institutions in contempt.

The tactical stand-downs in individual seats may give way to a much clearer pattern of non-aggression pacts at local level. No fewer than four tactical voting sites are poised to spend hundreds of thousands to persuade voters to form an anti-Brexit phalanx.

For now, the party machines have to resist this — and they are entitled to do so: the most important tactical voting recommendations are the ones that happen once you see which candidate is making progress in the detailed constituency polling all parties are doing.

For me, there are now only four realistic outcomes to this election, in descending order of preference:

— A Labour/SNP majority.

— A hung parliament in which the Lib Dems will only vote confidence in a different Labour leader.

— A hung parliament in which Johnson gets Brexit through with 19 Labour votes (yes, remember them?)

— A Johnson majority government which ennobles Farage, abandons all investigations into Russian interference and begins to erode the rule of law.

To Labour stalwarts who ask why I am discounting a simple majority Labour government, the answer is Scotland — even if all seven Labour MPs there survive, if the SNP win every Tory seat in Scotland, Labour will have a moral duty to try to agree at least a confidence and supply arrangement, with the offer of “devo max”.

If you survey these four realistic outcomes, the top two are a lot better than the bottom two. Tactical voting and non-aggression pacts can deliver the least worst option for progressives. Though some of the tactical voting advice has been hideously partisan, at least one site — tactical vote — looks sensible and legit.

I will spend the next three weeks pushing hard for a Labour government — but we've all done our duty to our party. For some, the time may come to do our duty to democracy, tolerance and the rule of law.