The election on 12 December is the most important for this country in generations. Not since 1945 or 1979 has the choice on offer been posed so starkly: between a government for the many, against the few; or a government of the few, against the many.

Jeremy Corbyn’s campaign launch speech made the dividing line crystal clear. We will either have, in the Tories, a government committed to completing the programme Margaret Thatcher began all those years ago – a government of the rich, for the rich, and by the rich, larded over with racism: an acceleration into a free market dystopia of national neoliberalism and runaway climate change.

Or we will have, in Labour, a government for the great majority: a clean break with a failed past, and clear vision for the future: the NHS funded and secure; free education for all; investment to create good, secure jobs, where the Tories have created deserts; the wealth of our country spread fairly, and placed in the hands of those who produce that wealth; and action on climate change and the environment that will make this country a beacon of hope for the globe. All of this is within our grasp.

We know this can be done. Just look at the flying start the campaign has made: £100k in donations to Momentum; £400k to the Labour party itself; 2,000 people logging on for an online campaign briefing; hundreds across the country on the phone banks; people taking days, even weeks, off work to help out; mass canvassing in the key seats Labour has to win to form a government.

Now that the election has been declared, Labour can get out of confusing parliamentary manoeuvres and get back to addressing real issues. Boris Johnson’s ‘parliament versus the people’ framing simply will not work so well if parliament isn’t sitting. This isn’t a new campaign – it’s picking up where 2017 left off, when people power and a clear political vision combined to overturn the supposed wisdom of the Westminster bubble and put a socialist within a whisker of Number 10. Now is the chance to make good on the promise of June 2017, and to put two-and-a-half wasted, miserable, pointless years of Tory rule behind us.

However.

There is precisely no room for complacency. The other side are not stupid, and they know we are prepared. Boris Johnson promised two things during his leadership election campaign this summer: to deliver Brexit on 31 October, and to smash Jeremy Corbyn’s Labour. He has failed on one. Now he will redouble his efforts to deliver on the second.

There’s a myth doing the rounds that the Conservatives lost their majority in 2017 because Theresa May ran such a bad campaign. This is nonsense: Theresa May – even with the gaffes and the slips, from the dementia tax to dodging the TV debates – delivered the biggest Tory share of the vote since Thatcher in 1983 – 42.4% of the electorate. Indeed, in absolute terms she won more votes than Thatcher in 1983 and 1979.

In 2017, close to 14m people signed up to the Tory manifesto and put their cross next to Tory candidates. Labour seats that the Tories specifically targeted – places like Mansfield – fell to the Conservatives, six seats in total. If it had not been for the surge in Labour’s support – lifting its share of the vote by the largest amount since 1945 – the story of the 2017 election would have been exactly as the pundit class gleefully expected it to be: massive Tory majority, May the new Thatcher, socialism back in the dustbin of history.

It was Labour success, not Tory failure, that cost the Conservatives their majority.

May had a strategy that worked. Johnson is sticking to the same strategy, in worsened circumstances – Brexit has festered; he is far less popular than May was – but with a (probably) more competent and (definitely) more determined delivery. It is a strategy based on scooping up the votes of those who voted Leave on the promise of Brexit, gobbling up competitors to the Tories’ right just as May gobbled up Ukip.

The headline message for the press is that the Tories are chasing after Labour Leave voters, perhaps in the ‘Rugby League towns’ of the north. Westminster journalists lap this sort of thing up, and duly troop off to vox pop whichever Corbynsceptic inhabitants they can get hold of in faraway places like Warrington or, apparently, Workington. This is largely a media story: the evidence we have suggests that, yes, whilst there are some Labour to Tory switchers, there aren’t enough to clinch the deal for the Conservatives. A more likely route is something like Labour-Ukip-Tory, or perhaps now Labour-Brexit-Tory, but there’s a limit to the number of Brexit votes that can be hoovered up – and too obviously chasing Brexit party votes risks losing the Tories’ real support in the south.

And there are two reasons to suppose that Brexit itself will not be quite the magic bullet for the Tories. First, failing to deliver the one thing you promised to deliver is never a good look, and whining about how the opposition prevented you from doing so doesn’t change that. You’re still basically a whiny failure, and if you can’t deliver on what you said was your number one priority, how can you be expected to deliver anything?

Second, the belief that many, many people are sick of Brexit and just want it out of the way is completely accurate – but then why spend six weeks of a campaign talking about something people are sick of? It’ll appeal to your own base, perhaps, but you won’t get much further. The Tories will need to pull off some serious policy moves to get out of it, and it’s not clear that the flimsy offers on the NHS, schools and the police we’ve seen so far are enough to do it. Coupled with the clear evidence that the Tories wish to use leaving the EU to end protections at work and privatise the NHS, Brexit may not be quite the free gift the Tories seemingly believe it to be.

No, the Tories’ real strategy – as the attempts at introducing voter ID suggest – is voter suppression: as far as possible, keep potential Labour voters at home. Demoralise and disorientate them. Create a story in which Johnson the Unstoppable Brexit Machine will simply steamroller through Labour’s support. Smear and slander Jeremy Corbyn and the Labour party so much that even their most die-hard supporters feel a bit uncomfortable turning out in the middle of December to vote.

Of course, this is hardly a positive or attractive vision. It’s not as good a media story as Labour heartland voters turning Tory. It’s just the ugly business of, as far as possible, persuading people not to vote. And it works: in every single one of the Labour seats the Tories won last time, the rise in turnout was below the national average. The Conservatives hoovered up their votes to the right, but Labour did not turn its side out.

Let’s be really clear about this: no vote should be taken for granted. There are huge reserves of Labour support in the places the Tories are supposedly targeting but that support has to be earned and earned again. The leader who lost Labour the most votes in the last two decades has not been – and will not be – Jeremy Corbyn. It was Tony Blair, who lost Labour 4m votes between 1997 and 2005 – many never to return. Cynicism in politics and politicians runs very deep. The task for Labour is to demonstrate demonstrate by its programme and actions that Jeremy Corbyn’s Labour can be trusted to deliver.

Nor should anyone think that Labour’s message is only going to work in traditional Labour areas, whether in the north or the major cities: longer demographic and economic changes mean places like Chingford in the London suburbs or Hastings on the south coast are seriously in contention. Just as there are well-off Tories in even the most heartland of the Labour heartlands, there are greater and greater numbers of worse-off potential Labour supporters in the truest of true blue areas – and long-run economic failure means their numbers are growing faster.

If we want to win, we need to do everything possible to mobilise our side: we need a bold vision to cut through the Brexit fog; but we need every single Labour member and supporter out there and campaigning to make it happen. In a world where no one really trusts journalists, or the media, or even – god forbid – politicians, members are the key resource, since it is face-to-face contacts that can cut through. You trust your friends, your family, your colleagues, even someone sincere and convincing on the doorstep more. And the basic message we have – of addressing inequalities, funding our services, and offering a future – can be taken to every part of the country.

We should know that the world is turning in our favour. 2017 wasn’t some aberration: it was a result that grew from almost a decade of austerity and four decades of neoliberalism. Corbynism has grown in that fertile ground, and more years of Tory misrule have simply watered and fed it. We can win this. But be prepared for the fight of your lives.

James Meadway is a columnist for Novara Media. He was formerly economics advisor to John McDonnell, the shadow chancellor.