It is never easy to judge the significance of any major event, especially one as momentous as September 11. Looking back, it is perhaps surprising that we were quite as shocked as we were. After all, there had been at least one serious attack on the United States itself in 1993, and many more against its assets in the following years. Certainly, President Clinton understood the scale of the threat and warned the incoming Bush team that bin Laden would be his number-one problem. Extraordinary though the attack was, what was truly stunning was how the US reacted.

Few people expected anything less than a serious American response against the Taliban and its allies in Afghanistan. Indeed, with a few odd exceptions, most of the international community supported such action, even when Washington went it alone without its main NATO allies. But what could not have been predicted was the scale of the decisions then made by the Bush administration: It declared a war, made it global and gave it a meaning that went far beyond what many thought strategically prudent.

The administration then made the decision to involve everybody deemed a threat to the US. This proved crucial. It turned what had been regarded as a legitimate war of defence into what many came to see as a war of imperial retribution. It challenged the basic principle on which the whole United Nations system was based: non-interference in the internal affairs of other states.

And it provoked a backlash against the US and Bush that not only included the wider Muslim world, but also sucked in large sections of European opinion and most of the Third World. It also led to a drawn-out conflict within Iraq that cost dearly the Iraqi people; that strengthened Iran’s position in the region; and proved useful to violent jihadists worldwide. If the purpose of liberating Iraq was to bring stability to the Middle East or make the US more secure, then by any measure, it was a terrible and costly failure.

Why then did the Bush administration translate September 11 into a war that became much larger and altogether more risky? The people responsible for September 11 were a particularly obnoxious group of zealots who had commanded very little support in the Islamic world. We still don’t have an agreed answer.

The fact that academics, bloggers and conspiracy theorists continue to debate the point implies something deeply worrying for the US: that very few people today (including those with no particular animus against it) believe the US unleashed its military might against Iraq as a response to either a serious threat posed by Baghdad, or as a way of spreading democracy. It was “oil”, the “Israel lobby” and the “neo-cons” cry one group; “classic empire building” another; or even perhaps the religious beliefs of Bush himself.

Either way, the US emerges with not much long-term credit. Little wonder that however hard Obama has worked to restore US standing—and his efforts have paid important dividends, especially in Europe—there remains a large question hanging over America’s claim to be both the indispensable nation and that proverbial “city on the hill”.

That the Bush strategy of unilateral pre-emption left the US in a weaker international position is now beyond dispute. Nor can we doubt the impact which a drawn-out war against an apparently unbeatable enemy has had on perceptions of the US itself. In fact, one very obvious measure of this is that when Bush assumed office in 2000, many were talking then in almost rhapsodical terms about the US as some new Rome on the Potomac; whereas when he left, people were debating something that had been off the agenda for at least 15 years: was the US now in terminal decline?

It would of course be plainly absurd to trace all this back to September 11. But September 11 is beginning to look like that classic crossroads moment when the US was confronted by a massive challenge. If it had responded more wisely, it might have secured its position in the world for decades to come. It had found itself in a similar situation just after World War II when asked some difficult questions about how to rebuild a world order after one great depression and another even bloodier war. The US had come up with imaginative policy answers that had united allies, limited the reach of its enemies, brought Americans together, and perhaps most critically of all, had sent a very clear message that it was more than just a powerful state with nuclear weapons and the largest military on earth. Rather, it was a nation that could be trusted to carry its big stick with great care.

How different the world that followed September 11. In this special sense, perhaps the real tragedy of what occurred was not only that 3000 innocent people lost their lives; it was that the US failed to translate this crisis into a new grand strategy. We may still live in a largely liberal world order, and with Obama in charge of the White House there are reasons to hope. But even his rare intelligence and energy will find it difficult to undo the damage that has been done to American prestige in the name of fighting terrorism.

Bin Laden may no longer be with us, but a decade on, his deliberate provocation of 2001, quite consciously designed to force America to overreact is still bearing political fruit.