"Order was the dream of man," wrote Henry Adams. "Chaos, the law of nature."
Autumn had already started in the English seaside city of Brighton in 2001, when Tony Blair stepped up to the podium to address his political party's annual conference.
As leader of the Labour party and the prime minister of the United Kingdom, this was his opportunity to talk strategy and vision to his core political supporters, still exuberant after their second and emphatic general election victory four months earlier.
But Blair had a greater horizon. Another coastal city, across the Atlantic, had been shattered exactly three weeks earlier.
"This is a moment to seize," he told his party faithful of the September 11 attacks. "The kaleidoscope has been shaken. The pieces are in flux. Soon they will settle again. Before they do, let us reorder this world around us."
Blair's speech struck a chord, fitting into the mood music, then rising across North America and Europe, that the 9/11 attacks marked the beginning of a new era.
What that new era represented varied: the start of a great clash of civilisations; the crash of the developing world into the developed; an opportunity to enact long-devised plans.
But 9/11 really represented an event horizon.
Beyond it, the world would be very different. Out of chaos, order would be brought. Unfortunately, that principle also worked the other way around.
Blair was not alone in his fervent belief that 9/11 represented an event of a different order of magnitude to any other of that generation, and that it fell to the leaders of select nations to react in a suitably historic way.
George W Bush, then-president of the United States, came to believe the same thing.
In time, this joint belief began a march to war that would lead to an invasion of Iraq, an invasion, 10 years ago, that would end up breaking the West.
Bringing order out of chaos had been tried twice before in the previous century.
Two world wars substantially reshaped the old order. By the time the Second World War ended in 1945, the old empires were defeated or exhausted: the First World War had taken with it the empires of the Ottomans, the Russians and the Austro-Hungarians; the Second World War took with it the aspirations to empire of Germany and Japan.
But the victorious empires had also borne a heavy burden. With great humiliation, France had been occupied, and Britain and Russia, although triumphant, were utterly spent. Europe was in ruins.
In the years after the war, these countries, together with the US, sought to remake the international order, to set in place a framework that would ensure that no one country could have a disproportionate impact on the world; that the interests of one country could not impose themselves so destructively on others. Europe was especially concerned about Germany and Asia about Japan - two giants that had affected their regions with their raw power.
The League of Nations, the forerunner to the United Nations, had tried to do something similar on a smaller scale, to ensure that regional disputes did not flare up into significant conflicts. But it could not stop powerful countries pursuing their own interests. When, in 1932, Japan invaded the Manchuria region of China, the League could do nothing but ask the Japanese to leave.
Out of the Second World War came the UN, along with complementary organisations such as the International Court. These were the foundations of the international order, an attempt to knit together the world through multinational institutions and international rules so that disputes could be resolved peacefully and big nations could not impose their will on smaller ones.
The second half of the 20th century is a story of how that project played out in the background, while the US and the Soviet Union fought for international dominance. But, after the collapse of the Soviet Union, that project suddenly had a new relevance and the genuine possibility of being achieved - with one exception.
The US of 1945 was not the US of 1991. The intervening half-century had seen the US take up the mantle of global power vacated by the European powers, especially Britain; at first unwillingly, but then with increased vigour, the US had projected its power overseas, with varying degrees of success, shaping policy and governments to its advantage.
With the US now the world's chief power, the reality of world power was about to be tested. If the US was really a benign influence, it would subordinate its power imperatives to multinational institutions such as the UN. The rules that it had helped set in place would themselves constrain the US.
The Iraq war of 2003 was the first major test of the international order since the end of the Soviet Union. Could the international system constrain the US?
The 2003 invasion of Iraq was a raw power war, a war prosecuted solely for reasons defined by the prosecutor. Unlike in Afghanistan in 2001, there was no immediate, compelling reason for the US to invade Iraq. Under the UN Charter, force could only be used against member states in response to a threat (self-defence was the argument invoked by Nato against Afghanistan and the Taliban in 2001) or if authorised by the Security Council to restore peace and security. Despite furious rhetoric to the contrary, neither of those conditions pertained.
The closest thing to authorisation from the world body was resolution 1441, passed by the Security Council in late 2002, which found Iraq "in material breach" of previous resolutions and threatened "serious consequences" for continued violations. Those consequences remained unspecified and some of the best legal minds have argued over the phrase for a decade.
The US at the time said explicitly that they would return to the UN Security Council for a further resolution before taking military action. But in early 2003, it became clear that the Council was sceptical and that the US would not be able to secure a second resolution with a clear mandate to attack Iraq.
It was at this point that Iraq became a test of the international system. If the US lost the political argument for the war and lost international support, could it still invade Iraq? Could the US step outside of the international system that it was itself a key backer of and still carry out a war of choice?
The answer came on the morning of March 19, 2003, as the US military led a coalition of forces "by air, land and sea" against Iraq. The first raw power war of the 21st century had begun.
In essence, what happened in the run-up to the invasion was that the US found itself bound by the strictures of international law. Iraq was a clear test of the international framework and when the war went ahead, it broke the rules that the West had fought so hard to impose after the Second World War. The framework created to hold back Germany and Japan could not, in the 21st century, hold back the US.
The Iraq war was the US's moment of imperial over-reach, its attempt to "remake the world around it". And it was the moment when the notion of a robust international framework collapsed.
The Iraq war also broke a smaller narrative that had taken hold in the days immediately after the ousting from power of the Taliban from Afghanistan, that the US should take up the mantle of imperialism long vacated by Britain.
The argument, made by a panoply of academics and politicians, swam, so to speak, in the same swamp as the call by Tony Blair, three years before 9/11, for what he termed "liberal interventionism", the idea that the developed nations of the world ought to impose their order (and thus their will) on smaller nations, in the name of stability and peace.
The chief proponent of this argument after 9/11 was the historian Niall Ferguson: when he wrote, in 2001, soon after the US went into Afghanistan, that "political globalisation is a fancy word for imperialism, imposing your values and institutions on others", he understood the situation clearly. The US was engaged in imperialism, even if it did not consider itself an imperialist nation - and Ferguson wanted more of it.
"There is no excuse for the relative weakness of the US as a quasi-imperial power," he wrote. "The transition to formal empire from informal empire is an affordable one." Absent, as more thoughtful writers subsequently pointed out, was any consideration for what "formal empire" would mean for the peoples and nations subjugated.
Even those closer to the levers of power believed it. In a much-quoted example from 2004, a senior aide to President Bush told TheNew York Times the mindset surrounding the US president.
"We're an empire now, and when we act, we create our own reality," said the aide. "And while you're studying that reality, we'll act again, creating other new realities, which you can study too, and that's how things will sort out. We're history's actors - and you, all of you, will be left to just study what we do."
This marked the change from so-called "polite imperialism". It exposed the raw power base of what the US was trying to do. But as the US became more bogged down in Iraq, as the insurgency came close to overwhelming US troops, that narrative vanished completely.
The frenzied fantasies of the neoconservatives that Iraq would be merely one stop on a global tour of creative destruction - Syria and Iran, for starters, then elsewhere - evaporated as US troops struggled to impose their will, first on districts, then cities, then whole provinces. By 2006, three years after the invasion, the insurgency in Iraq was at full strength and the US struggled to maintain control of even the main road from the Baghdad airport. Plans were drawn up for an evacuation of the Green Zone in central Baghdad. The rose-tinted views of what imperialism-lite was like changed: the US was trying to frantically extricate itself from Iraq, and no longer pondering further military engagements in the region. The dream had descended to chaos.
The chaos unleashed by the US in Iraq was astonishing. The reality of the years that followed was broken bodies and shattered dreams; the burying of loved ones and the dispersal of hundreds of thousands, dragging their families, possessions and memories to strange new lands, living among people who spoke a different language and breathed a different air.
Yet, from the vantage point of years later, it is clear that the Iraq invasion had other implications for international relations. It broke the notion that every country in the world was subordinate to international law and that's why it broke the West.
The unravelling of the idea of a global order built on laws was a significant event, one that will eventually have repercussions far beyond the territory of Iraq.
That the US failed to remake Iraq is at least an ambiguous result. In one sense, it is a tragedy that America failed so disastrously in Iraq, because the shattering of that state had a horrific human toll.
The US was not able to reorder the world around it - member states of the UN still stood against the US over Iraq, and the institution as a whole could not be brought to merely do the bidding of one powerful country. Yet that the US could still carry out its war without international legal backing showed the inadequacy of a world body that could not contain the aggression of its most powerful member.
Wider than that are other repercussions, some of which are now being felt, not all of which are immediately obvious. They will become clearer in the coming years. One immediate consequence of the unravelling of the global order is that the next rising power, China, will find it harder to agree to be bound to a western-led international framework that even the West won't adhere to. If the US will not adhere to international laws on war, the Chinese will ask themselves, why should China agree to international laws on human rights, on climate change, on copyright, on spying, on cyber-warfare?
The consequences for the idea of intervention in conflicts are also still with us: they overshadowed the discussion about entering Libya and Mali and overshadow still the discussion about the conflict in Syria.
The mistake of Iraq, from the vantage point of history, was a failure of imagination, a failure to imagine that remaking the world would have only one set of consequences.
While, the extraordinary events of 9/11 had shaken Tony Blair's narrow kaleidoscope, the hubris of the West came in not seeing that, for Iraqis, the invasion of 2003 was an equally extraordinary event, one that set the pieces of that society in flux. Iraqis sought to reorder that new world of a shattered Iraq as much as the Americans. Others joined them. Out of the stagnant order of Iraq was brought forth the chaos of freedom. History's actors, it transpired, had to share the stage with many others.
Faisal Al Yafai is a columnist for The National