When will historians of the future date the beginning of the decline and fall of the American empire?

The question may seem presumptuous. The idea that the American Century is a relic of the past, and we are entering a "new world order" of divided rather than hegemonic power, is relatively new, and still controversial. There are those who insist it ain’t necessarily so, primarily neocons of the second mobilization such as Robert Kagan, who are quick to reassure all right-thinking patriotic Americans that we’re still Number One and warn against the fatal lure of committing "superpower suicide."

To the rest of us, however – that is, to everyone outside the neocons’ cultic universe – the signs of the Great American Contraction are everywhere, most noticeably in the incomes, productivity, and general economic well-being of ordinary Americans. Our own CIA – never a friend to the neocons, but that’s another story – avers this condition is the single greatest threat to our national security: not Iran, not terrorism, but the very real threat of national bankruptcy. Our national debt is over 100 percent of GDP.

I would make the case, however, that the seeds of American decline were planted much earlier, during the cold war era. And if I had to pick a specific date that marked the beginning of the end, I would settle on January 31, 1968 – the day the Viet Cong and North Vietnamese forces began the Tet offensive, which was militarily a setback for them, but politically disastrous for the administration of Lyndon Baines Johnson.

Tet was costly for the Viet-Cong and North Vietnamese forces, but their decision to launch an all-sided assault on South Vietnam’s cities wasn’t entirely calculated for its military effect. As General Giap put it years later: "For us, you know, there is no such thing as a single strategy. Ours is always a synthesis, simultaneously military, political and diplomatic – which is why quite clearly, the Tet offensive had multiple objectives."

Militarily, their success was uneven and hardly decisive: they did not take any major cities, and those villages they took they couldn’t hold on to. On the diplomatic and political front, however, they came out the clear victors: their goals were to drive a wedge between the South Vietnamese government and Washington, on the one hand, and between Washington and the American people on the other. Their bold attacks on Saigon itself, which underscored the weakness of our South Vietnamese sock puppets, achieved the former, while television footage of American soldiers rushing to stop an enemy that seemed to be everywhere achieved the latter. Public support for the war plummeted. Gen. William Westmoreland, commander of US forces in Vietnam, demanded more troops: his request was denied when the White House concluded the war was unwinnable. A few months later, Johnson announced he would not seek reelection.

But of course the war wasn’t unwinnable, as conservatives at the time protested: we could have sent the 200,000 troops Westmoreland requested, and initiated a Vietnamese "surge" which might have pushed the Viet Cong back. Indeed, we could have sent a million men into that carnage, and the reason we didn’t was because it was no longer politically possible. The country had turned against the war and not even a stream of scare-mongering red-baiting invective coming from the neoconservatives of the day could turn the tide.

Today, the neocons bitterly denounce what they call the "Vietnam Syndrome," bemoaning its deleterious effect on their various schemes for world conquest, and – from their perspective – they are right to do so. Because if you worship at the altar of the war god, this Syndrome is a dangerous heresy: it means that the default of American foreign policy is caution rather than rollicking recklessness, prudence rather than mindless belligerence, realism rather than utopianism armed.

Of course, this did not mean the US would no longer engage in wars of aggression: Reagan’s attack on Grenada, the invasion of Panama, the first Iraq war, the Kosovo adventure, all these and more showed that the Washington crowd had hardly surrendered their global ambitions. Yet you’ll note that none of these wars were all that successful, or popular – and all were over rather quickly, with no permanent expansion of the Empire’s frontiers. George Herbert Walker Bush, you’ll recall, earned the neocons’ eternal enmity when he gave the order for US troops to pull back instead of marching on Baghdad

The Vietnam Syndrome was temporarily sidelined in the immediate aftermath of the 9/11 terrorist attacks, but soon reasserted itself in growing opposition to the Iraq war. Our Afghan adventure has met the same fate, with the Obama administration trying to wind down this wildly unpopular war without giving the impression of a panicked retreat. Everybody remembers those helicopters hurriedly taking off from the roof of the American embassy in Saigon as the Viet-Cong marched in, and our rulers would rather not see a repetition of that edifying scene.

The Vietnam Syndrome is here to stay, and this is true for a number of reasons. The big problem for present day advocates of American imperialism is that we no longer have the resources to fight endless wars. Secondly, we don’t have the ideological motivation to engage in such a massive outlay of nonexistent resources: there is no competing ideology, like Communism or fascism, that serves as a credible enough threat. Efforts to replace the commie bogeyman with the specter of an Islamic "global caliphate" – never that convincing to begin with – foundered on the rocks of Al Qaeda’s apparent demise. (It’s alleged reappearance in such a marginal area as Mali only underscores the marginality of the "threat").

Thirdly, I would advance the speculative thesis that modernity is characterized by a turning inward on the part of individuals and nations: that a focus on the self-development of the individual, and his personal relations, is increasingly the trend as living standards rise and technology advances. Of course, this trend is not inevitable: nothing is inevitable when we’re talking about the choices human beings make. Some traumatic event could throw us back into pre-modernity, destroy the economic basis of our growing "isolationism," and embroil us in a series of wars. Nor is there anything necessarily admirable about this inward-turning trend: at its worst, it is simply narcissism, an unhealthy and debilitating obsession that can only end in a kind of cultural madness. Think of Nero fiddling while Rome burned.

In any case, the Tet offensive marked the beginning of the end of public support for our post-WWII foreign policy of global interventionism, and although there have been several attempts to roll back the Vietnam Syndrome since then, none have enjoyed anything but temporary success. Political support for grandiose foreign policy adventurism has simply evaporated, and no conjuring of ideological ghosts and demons – fear of "militant Islam," the alleged shame and perils of "declinism," nostalgia for the "American Century" – will raise it from the dead.

What this means, in the long term, is that America is slowly but surely retreating from the world stage – not out of any conviction, but out of necessity. The warlords of Washington may wish to conquer the world, but they are constrained from attempting to carry out their desires not only by economics but also by politics. The simple fact of the matter is that, after sixty or so years of global adventurism, America is economically and psychologically exhausted. We have neither the means nor the will to stay on the course set for us by the great internationalists of the 20th century. The 21st century is slated to be the age of a resurgent nationalism – which, in this country, has nearly always been inward-looking rather than outwardly aggressive.

In the short term, however, there is no telling what will happen, and before we reach the final stages of imperial senescence it may well be that we’re in for a whole series of bloody and debilitating wars.

It’s nice to know, however, that history is on our side. Now if only we can stop ourselves from blowing up the world before the curtain is drawn on the Age of Conquest.

NOTES IN THE MARGIN

I’m on Twitter quite a bit these days: you can follow me here.

Here is the link for buying the second edition of my 1993 book, Reclaiming the American Right: The Lost Legacy of the Conservative Movement, with an Introduction by Prof. George W. Carey, a Forward by Patrick J. Buchanan, and critical essays by Scott Richert and David Gordon (ISI Books, 2008).

Buy my biography of the great libertarian thinker, An Enemy of the State: The Life of Murray N. Rothbard (Prometheus Books,2000), here.