From this point in the coverage of an election, everything shrinks into minutiae. Whose campaign bus is hurtling into what marginal? Which niche of voters is being wooed by the small print on that policy? Whose poll lead is getting squeezed? What fun it is to play trivial pursuits! Yet it jars a little in this election, because this one bears such significance. Not just for the next five years, not only over Brexit and not solely in the UK. This election puts Britain at the frontline of the international political battle of our time. The votes we cast on 12 December will shape the answer to two questions of far-reaching importance.

The first is whether the new hard right can be beaten: whether our democracies can put a halt to the forces represented here by Boris Johnson, or around the world by Donald Trump, Matteo Salvini and Narendra Modi, to name just a few. If we cannot block these nationalist hardmen democratically, then they will deform democracy until it is unrecognisable and illegitimate.

Labour’s new manifesto puts the party squarely at the cutting edge of what is now mainstream leftwing

The second big question is if the new left is yet capable of winning power. The generation radicalised by the banking crisis of 2008 – and which camped on Wall Street and outside St Paul’s cathedral, before marching against austerity and climate chaos – now provides much of the energy for Labour, the US Democratic party and the European left. Post-crash politics has gone mainstream; it is yet to be seen whether it can go into government.

Since the summer, the UK has been governed by a prime minister who in the referendum of 2016 told 350 million lies to the public, and who after entering No 10 tried unlawfully to shut down parliament. He has bullied when he should have united, fibbed when he should have been straight, and he has undermined an already shaky constitutional settlement.

Just like Trump, he exercises power by outraging democratic norms. The links between the two are underlined by yesterday’s leak from Jeremy Corbyn of trade talks between Whitehall and Washington. Those papers illustrate just what Jacob Rees-Mogg, Steve Baker and the rest of the hard-right headbangers behind Johnson mean by our “global opportunities” – bargaining away workers’ rights, food labelling and drug prices. Ministers may not have prompted or agreed any of these compromises, but they are where the fever-dreams of the new hard right inevitably lead a country like the UK, shredding its already tattered social settlement.

One section of the leaked document shows US officials telling their UK counterparts they will “ban” any “mention of greenhouse gas emissions” in negotiations. If, as Johnson has claimed, this is “pure invention”, he has the perfect opportunity to deny it in public next week when Trump visits London. My hunch is he wouldn’t dare.

Against Johnson and Trump, the liberal establishment has so far reacted with proceduralism – with justified appeals to civility, with a blizzard of ingenious parliamentary amendments, with deep-voiced barristers in horsehair wigs. Yet this has had only limited success – because its opponents demonstrably do not care about liberal norms. And so each failure has chipped away further at our democracy.

Facebook Twitter Pinterest Democratic party presidential candidate Bernie Sanders and Labour party leader Jeremy Corbyn Composite: Sean Simmers/PennLive.com via AP/Matt Cardy/Getty Images/AP/Getty

Should Johnson be re-elected you can expect him to keep on attacking the country’s institutions. At this autumn’s Conservative conference in Manchester, I sat in on a Brexit fringe event where a QC proposed the abolition of the dangerously independent supreme court. His fellow panellists – including John Redwood, Arlene Foster and Mark Francois – did not protest but merely nodded in assent.

So what’s left to oppose the nihilists and denialists of the hard right? Only politics, of course, which in England and Wales primarily means Corbyn’s Labour. In all the focus on the leader, what is less often interrogated is the change in the party’s grassroots. Reporting on Labour’s ground campaign, I was struck by how many of the most engaged activists had been involved in protests over student fees at the start of the decade, or other social movements, and had opted to throw in their lot with parliamentary politics. In the space of just a few years, they had gone from getting kettled by the Metropolitan police to sketching out policies for government.

Something similar has happened across the western left. The indignados of Spain had Podemos, and many of the marchers on Athens’ Syntagma Square supported Syriza. In the US and the UK, the social movements opted to try to reshape two of the oldest and most fossilised parties of all. Occupy Wall Street organisers I met in 2012 are today vying to make Elizabeth Warren or Bernie Sanders the Democrat choice to go up against Trump next year. And then there is Corbyn’s Labour.

Electability or even taking power was not traditionally much of a concern for that strand of the left. Corbyn stood to be Labour leader in 2015 to make a point. MPs put him on the ballot paper to give him a say. To put it mildly, this is an experiment that went beyond either side’s expectations – but it is hard to imagine the party going back to its pre-2015 configuration. It is impossible to imagine a Labour frontbencher following the example of former shadow chancellor Chris Leslie in 2015, and pleading for the party to back landlords.

Labour gets support from Bernie Sanders campaigners in US Read more

As Michael Jacobs, a former adviser to Gordon Brown, says: “It cannot now be taboo, anywhere, to talk about capitalism, the huge inequities of income and wealth, the unsustainability of the economic system, the power of corporations and media empires to set the limits of debate and govern policy, and how all these need to be radically reformed.” Brown didn’t do it, he admits, while Ed Miliband timidly cleared his throat on the issue.

But Labour’s manifesto puts the party at the cutting edge of what is now mainstream leftwing thinking: it calls for workers to be given stakes in their employers’ firms, for taking back utilities under public control, for a green new deal, and for a universal basic income. No other major party in the west comes close to this ambition. In fact, Sanders has taken some of the ideas. This is not to heap undue praise on Labour’s platform. As a policy document it is not without its contradictions; as a political statement, it runs the risk of passing over the grinding reality of the here and now experienced by most voters, in favour of some gleaming spire of progress. Why flirt with a universal basic income when, this week’s headlines show, some low earners could wind up paying more tax under your proposals? Why should renationalising rail take priority over ensuring more buses between towns and villages? Most of all, Labour has done little work to win public support or understanding for some of its bolder ideas.

But still the choices in front of us are stark. Western politics has often been jointly defined by US and UK leaders. Roosevelt and then Attlee defined social democracy; Reagan and Thatcher ripped down that edifice. Blair and Clinton set off together on the third way. The next generation could be defined by Trump and Johnson – or it could have hope instead.