We thought the United States would step back from the abyss. We believed, and the polls led us to feel sure, that Americans would not, in the end, hand the most powerful office on earth to an unstable bigot, sexual predator and compulsive liar.

People all around the world had watched and waited, through the consecutive horrors of the 2016 election campaign, believing the Trump nightmare would eventually pass. But today the United States – the country that had, from its birth, seen itself as a beacon that would inspire the world, a society that praised itself as “the last best hope of earth”, the nation that had seemed to be bending the arc of history towards justice, as Barack Obama so memorably put it on this same morning eight years ago – has stepped into the abyss.

Today the United States stands not as a source of inspiration to the rest of the world but as a source of fear. Instead of hailing its first female president, it seems poised to hand the awesome power of its highest office to a man who revels in his own ignorance, racism and misogyny. One who knows him well describes him as a dangerous “sociopath”.

And what awesome power he will soon have. Republicans did not just defy almost every projection, prediction and data-rich computer model to win the presidency. They also won the House of Representatives and much of the Senate. Trump will face few checks on his whims. A man with no control of his impulses will be unrestrained, the might of a superpower at the service of his ego and his id.

The most obvious impact will be on the country he will soon rule. Just think of what he has promised. A deportation force to round up and expel the 11 million undocumented migrants who make up 6% of the US workforce. A ban on all Muslims entering the country, later downgraded to a pledge to impose “extreme vetting” on anyone coming from a suspect land. A giant wall to seal off the Mexican border. “Some form of punishment” for women who seek an abortion. And prison for the woman he just defeated.

People will say that all that was just talk. But they said that throughout the campaign, insisting that Trump would “pivot” to a more moderate stance, that he would become more “presidential”. He never did. And surely he will see this victory as proof that he was always right, that his instincts are perfect and never to be challenged. There is no reason for him to moderate at all. The office of Thomas Jefferson, Abraham Lincoln, Franklin Roosevelt and John F Kennedy is now his playpen. He can do what he likes.

This will be America’s ordeal primarily. But it will affect all of us. A reality TV star with no experience of either politics or the military will have the nuclear button as his toy. This, remember, is the man who reportedly asked several times, during a military briefing, why the US didn’t use nuclear weapons since it had them. This is the man who has said “I love war”. Whose proposed solution to Isis is “to bomb the shit out of them” and steal the oil.

Think of the anxiety this morning in Riga, Vilnius or Tallinn. In the summer, Trump told the New York Times he did not believe in Nato’s core principle: that an attack on one member should be met by a response from all. He seemed to see Nato as a mafia protection racket: unless the little guys paid up, they should be left undefended. Vladimir Putin – Trump’s hero, admired as the very model of a leader by the president-elect of the United States – will not need more of a hint than that. The Russian dictator will surely see his opportunity to invade one or more Baltic states and expand his empire. President Trump would only admire the macho swagger of such a move.

A trade war looms with China, the imposition of tariffs that could imperil the entire global trading system. America is about to turn inward, towards protectionism. The markets have already delivered their verdict on that. They plunged.

And what about our planet? Trump believes climate change is a hoax perpetrated by the Chinese. He will do nothing to reduce emissions: he does not believe they exist.

But beyond all that, there is another consequence of this terrifying decision, no less dark. Trump’s success has delighted white nationalists and racists in his own country and beyond. His victories in the key battleground states were hailed by David Duke, a former luminary of the Ku Klux Klan: “God Bless Donald Trump,” he tweeted. “It’s TIME TO TAKE AMERICA BACK.” The Dutch nationalist Geert Wilders was in similarly cheery mood: “The people are taking their country back,” he said, “So will we.” Marine Le Pen will feel the same jubilation, as will every other populist or nationalist who traffics in hate.

For they have seen the power of a message built on fear and loathing. It’s not good enough to say this is all about the economic anxiety of those who have been left behind, though that clearly played a part in winning rustbelt states for Trump. But it’s an incomplete explanation because Trump did not only win those voters. He won 63% of white men and 52% of white women. Not all of those were the left behind. A lot of them were people drawn to a message that was, in part and however thinly coded, about reinstating white privilege.

Who is to blame? The list is so long, from the Republican party to the media, from the pollsters and data nerds who got it so wrong to the Clinton campaign team that took onetime Democratic bastions for granted, including Clinton herself, who for all her strengths was a flawed candidate. You can condemn all of them, but on a day like this who really cares about blame? The most powerful country in the world is to be led by its most dangerous ever leader, a figure who could have walked out of a school textbook narrating the darkest history of the 20th century. The wartime holder of the office that in January will be Trump’s once told Americans they had “nothing to fear but fear itself”. That is not true today. America and the rest of us have plenty to fear – starting with the man who now stands on top of the world.