Donald Trump doesn’t read books. He leaves that to his chief strategist, Steve Bannon, the man rapidly emerging as the true power behind the gaudy Trump throne. Given Bannon’s influence – he is the innermost member of the president’s inner circle and will have a permanent seat on the National Security Council, a privilege Trump has denied the head of the US military – it’s worth taking a good look at the books on his bedside table.

Close to the top of the pile, according to this week’s Time magazine, is a book called The Fourth Turning, which argues that human history moves in 80- to 100-year cycles, each one climaxing in a violent cataclysm that destroys the old order and replaces it with something new. For the US, there have been three such upheavals: the founding revolutionary war that ended in 1783, the civil war of the 1860s and the second world war of the 1940s. According to the book, America is on the brink of another.

You’ll notice what all those previous transformations have in common: war on an epic scale. For Bannon, previously impresario of the far-right Breitbart website, that is not a prospect to fear but to relish. Time, which has Bannon on the cover, quotes him all but yearning for large-scale and bloody conflict. “We’re at war” is a favourite Bannon slogan, whether it’s the struggle against jihadism, which Bannon describes as “a global existential war” that may turn into “a major shooting war in the Middle East”, or the looming clash with China.

All this lust for bloodshed may explain why Bannon was unperturbed by the chaos and loathing unleashed by last weekend’s refugee ban, which he drove through with next to no consultation with the rest of the US government. For Bannon is an advocate of the “shock event”. He’s described himself as a “Leninist”, telling one writer in 2013: “Lenin wanted to destroy the state, and that’s my goal too. I want to bring everything crashing down.” It seems war is his chosen method.

People are beginning to take notice – and get alarmed. Twice recently I’ve been told of hyper-rational individuals, who made their fortunes reading the runes correctly now converting their wealth into gold – better to withstand the coming conflagration and collapse of the civilised order. The current edition of the New Yorker includes a report on escalating demands among the super-rich for apocalypse-proof boltholes, with particular interest in airstrips and farms in New Zealand as a “back-up”.

All this can seem hyperbolic, if not hysterical. But if such thinking is taking root, it’s because a delicate set of international arrangements, painstakingly assembled in the years after 1945, and which have prevented a world war for nearly 80 years, are now getting a kicking from three different directions.

First and most obvious, is Trump himself. Not content with declaring Nato “obsolete”, he has begun hacking away at key pillars of the western alliance. His phone call with Australia’s prime minister has been written up in part as jaw-dropping comedy, but recall that Australians and Americans fought side by side as allies for a century. The two countries have long shared intelligence without restriction. Australia’s loyalty is so great, it sent troops to fight in America’s doomed Vietnam war (when Britain stayed away). Yet Trump treated the country as if it were dirt on his shoe. It shows the extent to which this US president is ready to implement Bannon’s fevered dream – and “bring everything crashing down”.

But Trump is not the sole villain here. This week’s Brexit vote in the House of Commons was a reminder that Britain too is among those taking a mallet to our fragile international system. By leaving the European Union, Britain has made it a live question whether the EU can survive. Theresa May insists she hopes it does, but the fact of Brexit will speak louder than any words.

This was an argument the remain camp failed to put with sufficient force in last year’s referendum, but it is central. Europe has a history of bloody conflict stretching back many centuries. The only period of continental peace came when the nations of Europe combined in a community and then a union. Even to risk the future of that union is to risk the return of war in Europe.

Both these shifts would be damaging enough, but the combination is a true menace. It’s not just that Trump’s proposed EU envoy actively looks forward to the unravelling of the EU, hoping it goes the way of the Soviet Union. It’s that Trump sees multilateral cooperation as a limp-wristed strategy for losers, preferring to make bilateral deals that work for him. That triggers a Darwinian scramble, in which every nation looks out only for itself – and damn the arrangements that previously held the world together.

And of course all this has an effect on those actors outside the west, as they respond to these shifts. With a swooning admirer in the White House, Vladimir Putin now feels free to flex his muscles: witness this week’s offensive in eastern Ukraine. China is girding itself for a trade war, or worse, with Trump’s America. Meanwhile global jihadism rubs its hands as Trump, with his refugee ban, all but vindicates their warped vision – signalling to the world’s Muslims that, yes, Islamic State is right and there is no place for you in the west.

All this leaves liberals and the left in an unfamiliar, unwanted position. Progressives seek progress: their preferred stance is advocating for change, for improving on the status quo. But the great shifts of 2016 have left them – us – in a new place. Suddenly we find ourselves campaigning not for what could be, but for what was.

Take those rebel Labour MPs who voted against the triggering of article 50. They were singing hymns of praise for the status quo ante, for a union of European nations that has brought peace, co-operation and stability. Of course, in normal times they would prefer to be pointing out the EU’s flaws, demanding it go further in, say, environmental or worker protection. But the battle lines have shifted in these last 12 months. Now progressives are fighting desperately to hold on to what we’ve got, trying to stop the unravelling going any further.

Democrats in the US are facing a similarly queasy feeling. In the last few days alone, they have seen Republicans repeal laws that prevented coal companies from polluting freshwater streams and stopped US corporations secretly paying foreign governments for mineral extraction rights. Activists now find themselves campaigning not for new or better laws, but for the survival of old ones that were doing some good.

Plenty on the left will have disliked much about the postwar architecture that held up since 1945: too US-dominated, too tilted in favour of the rich and powerful. But now they see Trump and others take a wrecking ball to the UN, the EU and much else, they may be having second thoughts.

Because Steve Bannon is not destroying the old, clunky post-1945 order for the sake of a fairer, more equal, more interdependent world. He seems instead to dream of a bloody, fiery war that will kill millions – out of which will be forged a new, cleansed and even more dominant America.

It’s a terrifying vision. Next to that, any progressive should want to conserve what we have. If that makes us the new conservatives – with Bannon, Trump and the Brexiteers as the wrecking-ball radicals – then so be it.