It is tempting to view the events of September 11, 2001, as having shattered the faith in historical progress that had been the secular faith of the West since the Enlightenment. Its late 20th-century iterations dominated the thinking of American policymakers across the political spectrum, and its intellectual underpinnings ranged from Francis Fukuyama's idea of the "End of History", George Soros' practical reworking of Karl Popper's idea of the "Open Society", and Michael Ignatieff's contention that between 1945 and 1995, the world had been engaged in a "Revolution of Moral Concern", epitomised by the human rights movement.

After all, as late as early 2000, Western policymakers seemed more concerned with arguing about how soon democracy could be exported to virtually every important un-democratic corner of the world, with, of course, the obvious exception of China, which was somehow considered not to invalidate the thesis but to be some sort of billion- person outlier.

Where ancient atavisms were rekindled or modern evil manifested itself, there were always so-called humanitarian interventions, which, while they had got off to a rocky start—only succeeding in Bosnia when it was, in many ways, too late, and failing to materialise altogether in Rwanda—had been viewed as starting to realise their aims in Kosovo and Sierra Leone, which were hailed not just as what could be done but what would be done in the future. As Tony Blair put it in his 1999 speech to the Chicago Council on Foreign Relations, when the (American-led) West had to fight, it would fight in defence of its values as well as its interests.

No one imagined that these wars would ever come home, though unless one invokes words like hubris and nemesis, which, however resonant, are too metaphoric to be of much use as explanatory keys, exactly why this sense of invulnerability predominated is unclear. After all, there had been a number of serious terrorist attacks in Blair's United Kingdom, in France, and of course in the US, where an attack on the World Trade Centre had already been attempted in 1993.

And yet, what Blair had posited in Chicago was a future in which the wars the West would fight would be wars of choice against adversaries the West was assumed to be able to easily defeat. Meanwhile, the march of democratic capitalism was seen as being the sine qua non of economic success everywhere in the world, and thus was believed to be unstoppable. In short, whether one was talking about what had come to be known somewhat misleadingly in Europe and the US as humanitarian intervention, or of globalisation itself, the world we had supposedly entered was one in which we would face no existential threats or, for that matter, threats of any really serious kind.

There is a word for a vision of a world in which we in the West would always emerge victorious from the wars we fought, and in which we had already either won all the ideological battles, or soon would as the prosperity engendered by liberal capitalism laid the groundwork for a democratic order, even in recalcitrant China, and that word is utopia—a word that literally means no place or nowhere.

Enter Osama bin Laden, laughing. Whether or not one believes that the American belief in progress as the general rule in history came to dust in Lower Manhattan on that clear early-September morning, there is no doubt that the faith in the specific reigning secular progress narratives—global human rights, internationalised legal regimes, and, above all, the idea that liberal democracy was the only morally licit political system and that, sooner or later, it would penetrate to every corner of the world—took a terrible blow that day.

Since then, things have only got worse: rightly or wrongly, the Abu Ghraib photographs and the other revelations about the systematic use of torture against certain jihadist prisoners, as well as the disclosure of the secret rendition program discredited not only the Bush administration's democracy agenda, but the older and more well-established tradition of Wilsonian liberal interventionism as well.

The Obama Administration's much-criticised initial caution in offering support for the anti-government mass demonstrations in Tehran—after the Iranian dictatorship manipulated the presidential elections, and then, as democratic uprisings swept the Maghreb and the Arab Middle East—should be understood as reflecting President Obama's and Secretary of State Hillary Clinton's sense that reviving the rhetoric of the democracy agenda needed to be done very cautiously. One does not have to disapprove of the administration's actions (and I do not) to nonetheless agree with the conclusion drawn by Leon Wieseltier, a committed liberal interventionist, who wrote in The New Republic as Libya burned that President Obama worried "about the repetition of an old paradigm", and, above all, did "not want to be Bush".

Of course, had the overthrow of Saddam Hussein led to a democratic Iraq, as historians like Bernard Lewis and Fouad Ajami, as well as exiles like Ahmed Chalabi and Kanan Makiya had assured the Bush administration that it would, rather than giving rise to Shi'a sectarian rule (the war is over; Iran won), and the prospect of the disappearance of Christianity from one of its original heartlands; and had Afghanistan not increasingly come to appear like Vietnam redux, it is entirely possible that the events of September 11 would have reinforced America's confidence in her own interventionist mission abroad rather than bringing it into disrepute.

Rather than Obama not wanting to be Bush, the democracy agenda would be alive and well, and living in the Maghreb. For all the blows it has taken, the conviction that America is humanity's last, best hope is not just something US politicians say on the fourth of July. To the contrary, it is a belief—and it is worth pausing and reflecting about why "belief", a religious category, is the word that comes to mind—shared by most of the American policy establishment across the political spectrum, which still believes precisely what John Quincy Adams (who feared this impulse above all else but even in his own time saw its grip tightening on the American imagination) had famously warned against—that it is indeed the duty of the US to go overseas to "fight monsters", and to be the vindicator not just of its own liberty but of the world's.

Where Americans on the Left and on the isolationist Right have generally seen this impulse as an expression of an imperial Pax Americana, the mainstream view at its idealistic best has been, to quote Wieseltier again, that, "assistance does not compromise the autonomy of the assisted". The enduring power of this view can be gleaned from the fact that the Arab uprisings have led to calls from liberal groups who bitterly opposed the Iraq war and who have criticised the Obama Administration for its policies in Afghanistan and Pakistan, first to force the Egyptian military to overthrow the Mubarak regime more quickly and then for the establishment of military no-fly zones over Libya. This, in fact would be an act of war, as Admiral Michael Mullen, the head of the US Joint Chiefs of Staff, wearily explained in Congressional testimony on the matter.

Iraq and "AfPak" may have discredited democracy-building at the point of a gun, but the missionary impulse to either foment or at least assist democracy wherever in the world it shows signs of flowering continues to resonate in the American imagination and to be an important factor in the US foreign policy debate.

In this sense, as in a number of others, September 11 changed less than is commonly supposed. And when all is said and done, faith in democracy-building in particular, and the internationalist project in general, are only coherent if they are derived from an underlying faith in progress. It is essential to remember that, historically, faith is not one idea among many, or even the first among equals, but rather the fundamental assumption on which Western societies have organised themselves since the Enlightenment. It is too deeply ingrained for one event, no matter how catastrophic, to discredit it.

Indeed, the view of American liberals in the decade after September 11 mostly rejected the idea that liberal internationalism, up to and including the occasional use of force, had been discredited. Instead, American liberals blamed the Bush administration for having perverted a noble idea—a view that many Europeans shared.

A particularly crude but nonetheless highly influential distillation of this view can be found in James Traub's book, The Freedom Agenda: Why America Must Spread Democracy (Just Not The Way George Bush Did), published in 2008 at the height of the presidential campaign. As an absolutely unreconstructed liberal interventionist, it is not surprising that Traub's other great cause as an activist (he has pursued a distinguished journalistic career at the New York Times Magazine) has been as a champion of the United Nations so-called "Responsibility to Protect" doctrine, which, in important ways, is an attempt to internationalise and institutionalise on a global basis the idea of intervention on humanitarian or human rights grounds.

When Barack Obama took office, he appointed Susan Rice, Anne-Marie Slaughter, Samantha Power, and a number of prominent liberal interventionists to high positions in the foreign policy bureaucracy. But these appointments have had little practical effect, much to the disappointment of many of president's liberal supporters, who had hoped the new administration would take a much more human rights-based internationalist hard line, notably on the question of intervention in Darfur—a development that has been no small source of amusement for those American conservatives who still fully support the Bush-era iteration of the democracy agenda.

In their attacks on President Obama for supposedly not believing in the doctrine of American exceptionalism, the Right has emphasised the president's reluctance to put the US forward as both the defender and the promoter of liberty throughout the world. That attack has back-footed liberals, who, much as they disliked George W. Bush, also wish President Obama would shed this reticent, and, at least superficially, more realist approach to US foreign policy.

Eleanor Roosevelt once said that "wishful thinking is America's besetting sin". She was right, but the question is why. Part of the explanation, I think, is the conflation of America as a nation and America as an ideal. Before she went into government Anne-Marie Slaughter even wrote a book on the subject, called The Ideal That Is America: Keeping Faith With Our Values In A Dangerous World. Again, this is the language of religion, not secular politics. Slaughter's argument is that, no matter how often it has failed to live up to them, America was founded on essential principles of liberty, democracy, equality, justice, tolerance, humility, and faith.

But more significant is her view that it is these principles that bind the US together as a nation. If one believes this, and also believes in any form of Enlightenment universalism, then intervention is not so much a policy option as an existential requirement—the transposition, on a global basis, of the famous lines from the "Battle Hymn of the Republic": "As He died to make men holy/Let us die to make men free." Anything less and you risk tearing the American nation apart. In this, the distance between the interventionism of George W. Bush and that of mainstream American liberalism is less than either the Left or the Right normally asserts—a question of methods, not first principles. It is as if, were it to turn its back on the idea of American exceptionalism, there would no America left, at least none worthy of the name.

In this sense at least, despite the shock of the September 11 attack, it fits neatly into the "Ur-American" narrative of an evil world that it was America's duty and prerogative to redeem. Liberals mocked George W. Bush's millenarian language (particularly in his Second Inaugural Address), or the claim, still widely believed in the US, that the Twin Towers had been attacked because the terrorists hated America's "freedom", rather than as a response to specific US policies, above all, its support for the House of Saud, and, secondarily, its support of Israel.

But in reality, Bush's vision of the world was congruent with the consensus view in America of the inseparability of its moral identity from its specific policies. It is not only abortion and homosexuality: from Richard Nixon's "war on cancer" to feminist identity politics, and from the debate over tax policy to the one over global warming, every important initiative or debate in the US is moralised and expressed in the language of Reformation and Counter-Reformation. The attacks fit perfectly into that pre-existing template.

All that changed was the realisation that the 1990s had been a kind of fool's paradise in which Americans had imagined the fight was over. Instead, the fight was going to be harder, and it was even possible that America would not prevail, at least not totally, as the country had in all its previous wars with the possible exception of the War of 1812.

There has been a change in the US between September 11 and the present. But, counterintuitive as it may seem, the destruction of the Twin Towers had little or nothing to do with it. Americans had a place to put September 11. What they were unprepared for was the prospect of the country's economic decline. The housing bubble had masked this reality from most people until the Wall Street crash, but once that bubble had burst, the accumulated economic bad news about the country's changed circumstances could no longer be denied or glossed over. The country had become a debtor nation; the dollar was now a comparatively weak currency; and America's transportation infrastructure was now inferior not only by European but also increasingly by East Asian standards. Not just the public but, less forgivably, most of the policy elite had taken the economic hegemony of the US for granted, or, at least, had acted as if they did when they continued to speak of Washington as the decisive voice on foreign policy questions everywhere in the world, and to build a military whose only possible rationale could be the assumption that America would continue to play this role for the foreseeable future.

What the crash did was reveal how chimerical these assumptions had been. It is this reality, and its corollary, the rise of China and with it, the prospect of at least a bi-polar and in all likelihood, multi-polar world, in which the US would be a great power but no longer the great power; the "indispensable nation", as Secretary of State Albright put it in the halcyon 1990s.

September 11 was bearable; the, at least, relative decline of the US was not. It is in this context, far more than panic and resentment over President Obama's ascension, that the counter-revolution of the Tea Parties, right-wing talk radio, and Fox News, needs to be understood.

If the Tea Partiers say that Americans are "losing" their country, they do not mean that they are losing it to Osama bin Laden and the jihadis. Nor, I think, is their animus primarily racial, though doubtless there are some who feel that way. To posit a counter-factual, were Justice Clarence Thomas to resign his seat on the Supreme Court and run for president, the overwhelming majority of the Tea Party movement would not give a second thought to the fact that he is black. The counter-revolution is first and foremost a panic about an American future that will be inferior to the country's past. And that fear is economic first and cultural secondarily, while the so-called "long war" against the jihadis comes in only as a very distant third. The Islamists pose a security threat, but that threat leaves the basic structure of American exceptionalism largely untouched.

But the rise of China, and its increasingly global economic challenge to the US, does exactly that. Anne-Marie Slaughter may assert that it has been America's ideals that have bound it as a nation. But increasingly, it seems that economic hegemony and military invulnerability were the real glue. Marxism may be dead, but it seems we are all materialists after all.