The Fall of Pax Americana

This is the third article of our “Sacking of Rome” week: red-teaming the global order and learning from history.

“Thus, what is of supreme importance in war is to attack the enemy’s strategy…Next best is to disrupt his alliances…” Sun Tzu, tr. Samuel B. Griffith

This week, we are asked to consider what might bring down America’s global hegemony, considering for comparison the threats faced by Rome’s imperium over the course of its history.

The exact historical causes of the Roman Empire’s final fall (officially in A.D. 476, with the abdication of the last emperor, but arguably in A.D. 410, with the Visigothic sack of Rome) have been the subject of dispute since at least Edward Gibbon’s famous History was published, and will not be resolved here, but it is worth looking at some of the more plausible explanations. A rough consensus emerged in the late 20th century that by the end the Empire was bankrupt and unable to pay for its own defense. This led the anthropologist Joseph Tainter to argue the collapse happened when Rome’s subjects had the opportunity to defect to invading barbarians: the Roman state was too expensive to maintain and could not be made affordable, and the ferocious and appalling tax burden it placed on its citizens (which in extremis caused them to sell their children as slaves to pay their bills) caused them to look for any chance to join a different system; the barbarian incursions in the end were unopposed because, relative to the oppression of the Roman state, they posed less of a material threat. In Tainter’s view, the final collapse was, for the average Roman, a step up rather than down.

Despite the undeniable evidence (though we are, admittedly, working with archaeological specimens that are literally fragments and a handful of literary sources) that Rome was experiencing financial troubles throughout the era of the Empire (which caused it to debase its coinage in an attempt to get through seignorage what it could not through taxation), there is a contrary view, articulated most recently by the Oxford historian Peter Heather. In Heather’s argument, the Empire was doing relatively well financially at the end (the really burdensome taxation may have occurred more in the constant civil war of the 3rd century A.D. than the more peaceful 4th century, and may have had more to do with the depredations of marauding armies than the peacetime needs of the state), and was finally experiencing some domestic tranquility and normalcy. What brought it down was not its own internal rot, but a few well-timed heavy blows: just as Rome was having to arm itself to deal with a resurgent Persia, the Huns arrived in Europe, pushed Germanic barbarian tribes southward, and the combination of this and ineffective Roman diplomacy led to barbarian armies knocking at the gates. In Heather’s formulation, the final crash was simply the result of Germanic tribes operating in larger groups with larger armies in the field than they had previously, having been pushed in that direction by the Huns. Rome could not withstand the pressure, and it was defeated on the battlefield.

One could also point to the classic argument, which began with Edward Gibbon, that Christianity had made Romans less warlike, and that this, in turn, had made the Empire easy prey. This has been questioned in more recent times, but it may have had some effect.

Whatever brought Rome down, one can come up with a reasonably good synthesis of these proposed factors as a means of understanding what challenges await the U.S. One need only suppose that these explanations were all, to some extent, correct. Put in simple terms, the recipe for the downfall of imperium involves increasing need for defense spending, structural inability to cut costs, and a generalized apathy on the part of those within the “empire’s” bounds, combined with a changing geostrategic environment and war weariness at home. A few good, sharp knocks are then quite enough to bring it down. If one were looking for trouble for the U.S. in the near future, this is what one would look for.

At present, the U.S. is having difficulties maintaining its primacy and hegemony. Its defense budget, relative to its GDP, is in decline. Somewhat like Rome, its internal governing structure makes it difficult for it to avoid waste and intelligently allocate resources: at the moment, its political system is near-paralyzed, and whomever one may blame for this state of affairs, this makes it that much more difficult for it to respond to a changing strategic environment. At the same time, as I have noted in past posts, the U.S.’ geopolitical rivals have been rearming; one need only note the ongoing political maneuvers in the East and South China Seas and Russia’s incursions into Ukraine to discover that these rivals not only possess more power, but are increasingly unafraid to use it. In the face of these developments, the U.S.’ allies have remained apathetic: all of them likewise have internal political dynamics (the tradeoff between welfare benefits for aging populations and rearmament) that make it difficult for them to decide to do more, and in the case of Ukraine, economic incentives work against their involvement. The perception of U.S. weakness and reluctance to protect allies has not helped this dynamic.

The sharp shocks might come in the form of a series of crises in which the U.S. was unable or unwilling to act as the global guarantor that it claims to be. Russia under Putin is widely believed to have designs on the Baltic states, which on the one hand are demilitarized and notoriously difficult to defend, and on the other are NATO members that the U.S. is obligated by treaty to protect (the classic “can’t/must” dilemma personified). And while China’s actions with regard to the Senkakus, the Paracels, and (for that matter) Taiwan have to date mostly involved mere posturing, it is easy to imagine a future scenario in which China’s leaders were forced onto a more hawkish and nationalist path by factional rivalry within the ruling Party or by economic stagnation resulting in the need to distract its population.

What if a series of military moves by China and Russia happened against multiple U.S. allies at the same time? The so-called “two war doctrine” is now a relic, but the U.S. military’s capabilities are formidable, and it might be able to respond to attacks on, say, Estonia on the one hand and Taiwan on the other. If caught unprepared, however, it might be forced to cede initiative at least temporarily in one or more theatres, which might be enough time for either China or Russia to turn its takeover of a U.S. ally into a fait accompli. In effect, there is no guarantee that U.S. forces would be in position to stop an aggressive move before it was made and before it initially succeeded. At that point, the U.S. would face not only the cost of mobilizing for war (particularly if the military’s existing resources were inadequate to the task of retaking the lost territory), but also the risks associated with initiating or renewing a major conflict with two nuclear-armed great powers at the same time, possibly in the absence of immediate and substantive assistance from allies. Depending on the U.S. leadership, political situation, and public mood at the time, it is easy to envision political factions uniting around a dovish policy response, possibly with negotiation or ineffective sanctions used as a face-saving measure.

The consequences of such a policy would be disastrous for the U.S.’ international political position. Although the U.S. would retain its economy and (presumably) its armed forces, its allies would quickly make their own arrangements: a great power guarantor that has been shown to be uninterested in one’s protection is at best useless and at worst an unacceptable risk, and states that had previously relied on the U.S. to protect them from Russia and China might decide that it was safer to appease Russia and China. In two major geopolitical regions, the U.S. might quickly find itself friendless and alone.

Truly destroying a great power is difficult, but knocking it off its political perch can be done given the right mix of initiative and opportunity. The American equivalent of the Fall of Rome would be a world in which Americans awoke one morning to discover that they were no more influential than anyone else, and a good bit less than some in some places. The Pax Americana, like the Pax Romana, would give way to something new.

It must be stressed that this scenario is at the moment far-fetched, and far from inevitable. Avoiding it, however, will require a renewed commitment on the part of the American public to putting up the resources necessary to fulfill the role they want their country to play. A dose of political realism and willingness to compromise for the good of the country would not come amiss, either. Or, in Lord Macaulay’s memorable words about America’s mighty world-ruling predecessor: “As we wax hot in faction, in battle we wax cold.”

Martin Skold is currently pursuing a PhD in international relations at the University of St. Andrews, with a thesis analyzing the strategy of international security competition.

6 thoughts on “The Fall of Pax Americana”

  1. Awesome article. I would love to build on this theme by asking how do our friends and allies respond to the fall of Pax Americana and the Rise of Regional Hegemonies? To me, the answer is collective security with teeth (and lots of submarines).

    1. Thanks, Nicolas.

      I was painting with a very broad brush, but I do think that you’d probably see regional blocs form in some places – as well as a gradual shift toward acceptance of Chinese or Russian influence on the other. Depends in part on whether you can convince people in any given country that it’s worthwhile to pay extra for their defense. I’m not sure where the strategy and procurement angles you mention fit in there – want to write that article?

  2. Perhaps it is the end of the draft that will be the real cause. Rome fell because it outsourced its defense.

    It makes defense unaffordable.
    It separates the soldiers from the citizens.
    Lawmakers with military experience are increasingly rare.
    It permits stupid, irresponsible, useless waste of military resources because so few American families “have a dog in that fight.”

    1. I will say this much: I’ve never understood the “Rome fell because it outsourced its defense” line of reasoning.

      The Roman army was de facto professional from the middle of the 2nd century B.C. onward – a situation that was formalized by the Marian reforms at the end of that century. This was a full hundred years before the Empire as we know it was established, and more than five and a half centuries before the Empire fell. If “outsourced its defense” means “had a volunteer army,” then Rome lasted longer than the U.S. has so far by a factor of two or three.

      Conversely, the Roman Empire was no stranger to conscription. Gaps in the legionary ranks were almost routinely filled by conscription when there weren’t enough volunteers. There was also a “stop-loss” policy in effect at various points, insofar as enlistments were for 25 years but discharges were granted only in even-numbered years. Most provinces also had second-line militia units that often employed some type of compulsory service – the poet Ovid, exiled to the Black Sea, complained about having to pull reserve duty. After about A.D. 200 or so, we also read of soldiering becoming a hereditary profession enforced by law – a “backdoor draft” if ever there was one. The Empire, in short, was no stranger to coerced service. Nor did it habitually rely upon non-citizens for its defense – except in the eastern provinces, where there just weren’t many Roman citizens to begin with, the legions all were drawn from the Roman citizen population. (After Caracalla extended citizenship across the provinces, the distinction got pretty murky, but that just proves the point still further: it was all about the same in the end.)

      Then again, if you mean “relied on normal peacetime levels of military mobilization instead of universal service” – this was true all throughout Rome’s history (an agrarian society can rarely keep more than about 1 percent of its population in uniform at any given time), not to mention our own. Whether via a draft or a volunteer force, you’re not going to have universal exposure to military service in peacetime, and this is especially true in an agrarian society without a lot of economic surplus to mobilize.

      One might argue that selective conscription – which tends to fall on those sectors of society least able to shift the burden – is the worst of all possible systems: no universal exposure to military matters or shared sacrifice, and no voluntary specialization of labor, either – and it has all the attendant problems of poor morale and discipline in the ranks on the one hand, and discord at home, on the other. Rome transitioned to an all-volunteer force once it became impossible to keep citizen-conscripts overseas for years at a time on imperial policing missions. (Barry Strauss has a good essay comparing the late Roman Republic’s problems with military recruitment to those of the U.S. in Vietnam. It’s the same problem: to quote T.R. Fehrenbach, “Citizen-soldiers stand ready to die in holocaust, in the big war. Very rarely are they ready to die in anything less.” Everything Fehrenbach wrote about Korea could have been used to predict Vietnam.) If Rome encountered difficulties with soldiers being loyal to commanders rather than the state, it seemed to do so whether the soldiers involved were conscripts or volunteers – imperial police work in an era of limited transportation and communications just inherently entailed this problem. In fact, given that conscripted citizen soldiers lost their farms as a result of their service and had no other options but to continue serving, the line between “draftee” and “volunteer” got very blurry in the late Republic, which was the reason for the Roman transition to a volunteer force in the first place.

      Nor was Rome run by inexperienced politicians under the Empire (or even under the Republic). In the Imperial period, from Severus onward, emperors had to worry about revolts almost constantly and lived and died by the sword – no strangers to bloodshed there. Likewise, the Roman “cursus honorum” for official careers practically required military experience – the common gripe on the part of the grunts in the Roman army wasn’t that the politicians weren’t warriors; it was that their senior officers were inexperienced time-servers aspiring to be politicians who cycled out before they got to be any good at their jobs.

      The U.S. will always have a problem with lack of military literacy at the highest levels (and its general population) for the simple reason that it is a sea power settled by draft dodgers on the far side of the world from most conflicts. Such states practically never maintain large standing armies based on universal conscription (you can have a big army or a big navy, but rarely both); the fact that post-WWII we had an almost universally experienced population was an historical fluke, as well as the exception that proved the rule – the U.S. did not formally have universal conscription in WWII and did not institute it afterward. (I always find it particularly curious to hear people of the baby-boom generation extol the democratic virtues of universal service, military or otherwise – it’s as if they either have forgotten their formative years or are ashamed of them.)

      If there’s a solution to the problem of lack of experience in the U.S., it’s a combination of greater literacy in military matters on the part of the civilian population (at the very least, a willingness to treat military history as a legitimate subject of study), combined with engagement with the broader population by those who do know military matters firsthand – which I believe is what many of the service-members in this organization sought to do by forming it.

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