One of the many extraordinary things about the ancient Greeks is that their deepest thinkers – Aristotle, Plato, Sophocles and others – gave us words that almost 3000 years later help explain our modern world. After years working and living in the US, by September 11, 2001, I was back in London. When the 9/11 attacks took place I was walking in the late summer sunshine, preparing to go to my job presenting BBC news that evening. My mobile phone buzzed. I was called in early to begin presenting rolling TV news programmes for Britain and around the world. Those few hours were so much of a shock that much of the broadcasts remain a blur in my mind, as we tried to make sense of the almost incomprehensible hijacking of four planes by men who murdered some 3000 innocent people, and killed themselves in the process. After the TV make-up was wiped off my face, I drove home and stood in a hot shower, trying to make sense of this new world disorder. The US had been home to me for many years. Friends lived in New York, Arizona, Florida, Pennsylvania and Washington. I couldn’t sleep. In the middle of the night, three of those ancient Greek words started to form part of an explanation. We will get to the third word later, but the first two words were “hubris”, usually translated nowadays as “pride”, and second, “nemesis”, which can mean “punishment” for pride, or “revenge”. In Washington, hubris had been obvious throughout the 1990s. The Cold War was over. America won. Years of sacrifice meant thankless wars in Korea, Vietnam and elsewhere, the face-off known as the Cuban missile crisis and the hugely expensive commitment of US troops in Europe. But by the 1990s, Americans watched in amazement as their long-time enemy, the Soviet Union, fell apart. President George H W Bush spoke of a “New World Order” and a “unipolar world,” where the US was the “only superpower”. Some American intellectuals – unwisely – spoke of “the end of history”. Hubris? Definitely. But America triumphed almost everywhere in almost everything, from economic and military might to cultural and sporting success and turn-of-the-millennium innovations that changed our world – Apple, Google, Microsoft, PayPal, Facebook, Twitter, and all the rest. But after hubris, in ancient Greek tragedy, comes nemesis, punishment. Islamic fundamentalists living in caves in Afghanistan in pursuit of an ideology that violently rejected the dominant American culture, attacked America’s centres of political and economic power – Washington and New York. They did so with two weapons so primitive we have known them from the start of human history. Their weapons were knives and cunning. When I have talked with security experts about the 9/11 attacks – box cutter knives and pepper spray used to hijack planes to turn them into weapons – those experts have often reflected on the fact that Osama bin Laden’s strategy depended on luck. The hijackers managed to take over four planes almost simultaneously, forcing three of them to attack high-value targets, symbols of America’s financial and military might, the Twin Towers and the Pentagon. For years I had witnessed and reported on different kinds of terror, in Ireland, Latin America and home-grown American terror too, including the destruction of the Oklahoma federal building by the white supremacist Timothy McVeigh. When an Irish terrorist group, the IRA, came close to murdering British prime minister Margaret Thatcher, they issued a statement that sums up what security experts call “asymmetric warfare” between terrorist groups and governments. The IRA statement said: “Today we were unlucky, but remember we only have to be lucky once. You will have to be lucky always.” On 9/11 bin Laden’s hijackers proved that point. America’s luck ran out. A generation of Americans felt vulnerable to attack at home in a manner that no one had experienced since the Japanese attack on Pearl Harbour in 1941. And, like Pearl Harbour, 9/11 changed the world. Commercial air travel ceased. When transatlantic flights started up again – under the intrusive security measures that we now take for granted – I flew to Washington to report on the aftermath of 9/11. The hubris of all those deep thinkers from the 1990s, the idea that liberal democracy was inevitably going to take over the world, was duly buried along with the innocent victims of the attacks. What lived was a ferocious desire to strike back. That, as we all know, led to the invasion of Afghanistan the assassination of bin Laden, and the invasion of Iraq. But what also emerged, in this newly vulnerable superpower, was a twisted kind of logic. American politicians asserted, without any evidence, that Iraq’s leader, Saddam Hussein, was complicit in 9/11. That ludicrous assertion combined with claims that Iraq possessed weapons of mass destruction were used as justification for the US-led invasion. And that brings us to the third word from Greek tragedy, “catharsis.” It means a sense of cleansing, eliminating horrific events and hoping that something good will emerge from all the suffering we have experienced. Well, we can hope. We certainly have suffered. Mr Biden, in robust statements justifying the US withdrawal from Afghanistan, made clear that he sees withdrawal as a kind of cleansing. As Biden put it: “This decision about Afghanistan is not just about Afghanistan. It’s about ending an era of major military operations to remake other countries.” Twenty years on from 9/11, with Donald Trump still complaining about a supposedly stolen election, with deep divisions in the US over poverty, race, abortion, coronavirus vaccinations and other social questions, plus wildfires and floods attributed to global warming, an American catharsis, a cleansing, may still seem necessary. But it is also elusive. Perhaps Mr Biden can provide it. He could rewrite Donald Trump’s old slogan, by noting that re-making his own country after 20 years of impossible conflicts must begin at home. To avoid hubris, Mr Biden must not only put America First, he has to Fix America First.