Donald Trump – thrower of tantrums, constructor of vast conspiracies, pathological liar, sleazy snake oil salesman, malignant bully boy and oafish dotard – is a caricature of capitalist depravity and moral degeneration so repugnant that even the most inspired satirist could never have dreamt him up.

But here we are. If 2016 was the year the world was shocked by the twin earthquakes of Brexit and Trump, 2017 was the year in which president Trump became part of the fabric. Trump might go, later if not sooner, but the epoch he has opened, the rupture he has caused, won’t.

This is our world now. It is a horrible place. In Germany, Nazis are back in the Reichstag. Fascism is becoming a mass force in country after country across Europe. White supremacists have driven cars into crowds of anti-fascist demonstrators on the streets of US cities. The sunny days when left wingers were gently laughed at when they talked about the dangers of a fascist revival fade further from memory every hour.

To those of us who came of age in the era of triumphant liberalism after the end of the Cold War, history was presented as entirely past. Its terrible icons – the swastika, the nuclear bomb, the authoritarian state – existed in historical documentaries and other chronicles of an age long past, like monsters in a fantasy tale. Today, these monsters are coming back to life: one day incredible, the next day just how it is.

The possibility of nuclear conflict used to be considered, like Nazism, a memory from the middle decades of the 20th century. It is now once again a terrifying reality. The Hawaiian government recently announced it was resuming monthly drills of its nuclear attack sirens, which ceased in the 1980s. The problem is they stopped building civilian bunkers back then too, so there’s no room for many of today’s Hawaiian population. All they can advise is that, if Hawaii is nuked, people should stay indoors.

When Trump threatens “fire and fury like the world has never seen” and refuses to rule out a US nuclear first strike against North Korea, the most optimistic interpretation available is to assume this is the bluster of an impotent madman. An impotent madman in charge of a military machine capable of inflicting more death than any in the history of humanity.

In addition to old monsters revived, we have new monsters, unique creations of our age.

As ever more apocalyptic reports come out from environmental and scientific organisations warning of the dire consequences of inaction on climate change, the Trumpist right glories in its refusal even to recognise that there is a problem. In Australia, Liberal politicians wave bits of coal around in the parliament like petulant children – “Nah nah nee nah nah” – as they confirm their enthusiasm for massive new coal mines that would not only destroy forever the Great Barrier Reef, but could help tip the warming of the planet past a point of no return.

And now George Monbiot tells us that, bad as climate change is, it rates only third on the list of cataclysmic threats to human life on this planet caused by out-of-control capitalism. According to him, “two other issues have such huge and immediate impacts that they push even this great predicament into third place. One is industrial fishing, which, all over the blue planet, is now causing systemic ecological collapse. The other is the erasure of non-human life from the land by farming”.

If nothing else, this gives us perspective. At least the right bothers to furiously deny that climate change is a problem – they don’t feel compelled even to mention why warnings about the dire consequences of out-of-control over-fishing and farming are of little interest.

While the planet burns, our politicians fiddle. The Australian right – most prominent among them Malcolm Turnbull – have led the world in normalising Trump. Turnbull’s embrace of the orange abomination is particularly galling. When waxing lyrical about how much he agrees with the deranged US president, Turnbull affects a sly grin, as if to say that of course he doesn’t really agree with whatever lunacy of Trump he is defending, he’s just saying what he has to say. That’s politics.

But this politics is precisely how we got here. The entire establishment – in the US and Australia, and around the Western world – ploughed the ground for Trump. In the US the conservatives who now claim to oppose him have spent decades tolerating if not promoting racism as part of a cunning strategy to win office. Now they complain when they reap the whirlwind.

Here the Liberals did the same with refugees, Muslims and social reaction of every kind. Now they are surprised when the result is Hanson and Bernardi denouncing mainstream Liberals as communists in disguise. The ALP “pragmatically” goes along with every atrocious shift towards open barbarism in Australian refugee policy, and then blames everyone but itself for the appalling attitudes to refugees found in opinion polls.

On every question it is the same. As the world faces challenges of an increasingly epic order, the political establishment becomes ever more infantile, ever more incapable of seeing anything further afield than its own nose.

In some quarters – most notably the opinion pages of liberal newspapers like the Guardian – this state of affairs is much lamented, and contrasted with a nostalgic vision of great leaders past, men (almost always men) who understood how to lead a society through troubled times.

But this misses entirely the truth of our situation. Trump, Turnbull, Abbott, Shorten – and all the reactionary, opportunistic, simple-minded, gutter politics of our age that they represent – are mere symptoms. What we face – and what explains the craven ineptitude of all the leaders of the political class – is a fundamental crisis in the whole capitalist order. To paraphrase Lenin, it is not simply that the mass of people are increasingly unwilling to accept the old way of things, it is also the case that the old order of things can no longer be sustained, even on its own terms.

Capitalism is a system of crisis, and it is now in a crisis of epic proportions. Competition between great capitalist powers old and new has always led to turmoil – it’s what caused both world wars – but there has never been a power so great that is falling so fast as the US is today.

There has always been wealth inequality, but it has never been so great, or so starkly apparent, as it is today.

There has always been a gap between the ideological and civic apparatuses that try to manage popular unrest, and the lived reality and consciousness of the mass of the population. But it has rarely been so profound as it is today.

It is the complete failure and utter discrediting of the orthodoxies of liberal capitalism that have given rise to the monsters of the far right.

Donald Trump and his ilk are brought to you by the billionaire liberalism of Bill and Hillary Clinton, by the smashing of the left in the Labor Party, by the annihilation and co-option of the trade unions, by the decimation of social struggles of every kind by a liberal elite that refused to understand that its enrichment did not equal human progress and that its victories were not victories for a working class it once claimed to represent but had long since abandoned.

Trump is brought to you by a liberalism that said any remnant of actual leftism, any actual attempt to build a movement of solidarity among the mass of the world’s population against the savagery of free market authoritarianism, was nothing but historic anachronism.

And what of the left? In 2017 there have been hints of what a real alternative to both Trumpism and the discredited centre could look like.

In Britain, Jeremy Corbyn came within a whisker of bringing Labour to power on a radical program derided by the whole media establishment as well as the conservative timeservers who pass for Labour MPs.

In the US the sorry capitulation of Bernie Sanders into the Democratic fold has not erased the fact that millions of people hate Trump and the Clintonite centre with equal vigour.

Even in Australia, which has lagged sadly behind the politicisation that is beginning to grip the world, there is a growing sense of the need for a genuine left alternative.

But almost everywhere you look the left is way behind the curve. The ideological crisis in the system has produced an invigorated radical right and a collapsing centre, but not yet a new radical left.

The challenge of 2018 is to turn that around: to start to build a left that can take on not just the Trumps and the Abbotts and the Turnbulls, but the whole sorry system that created the desperate impasse in which we find ourselves.