THE AMERICAN All-Volunteer Force is not yet fifty years old. Though created in the late stages of the Cold War, it truly came of age during the post-Cold War period. It now faces its second great shift in strategic priorities, from the “small” wars of the post-Cold War international order towards renewed focus on near-peer competition—a focus which shows no sign of abating during the Biden administration. At the same time, with rising partisan polarization at home creating new concerns about the stability of civil-military relations, now seems a good time to take stock of both the benefits and drawbacks of the All-Volunteer Force.

Anticipating how well the All-Volunteer Force can cope with shifting strategic and domestic conditions is rendered difficult by its relatively short, in historical terms, existence. While it was created in the context of the Cold War, the All-Volunteer Force fortunately never had to rise to a direct near-peer conflict. Perhaps a historical analysis of past professional volunteer armies can serve to fill this gap, offering insight into the benefits and pitfalls of this kind of military recruitment system. Indeed, the professionalization and “volunterization” of the Roman army—often referred to, somewhat misleadingly, as the Marian Reforms—offer some particularly instructive lessons. Arising out of many of the same concerns that motivated the formation of the All-Volunteer Force, the professional Roman army was, like the current United States military, extremely effective and enjoyed a significant qualitative edge on the battlefield on account of its professionalism and discipline. At the same time, the process of professionalization also imposed new and sharp limits on Roman strategic options and eventually destabilized the Roman civil-military relationship, resulting in the army serving as the source of repeated upheavals which both destroyed the Roman Republic and repeatedly plagued the Roman Empire.

Could it happen here? Despite the often-optimistic assessments of the American All-Volunteer Force’s performance, many of these same drawbacks are becoming evident in the U.S. military. Much like modern defenders of the All-Volunteer Force, the Romans seem to have thought that their professional army could be scaled up in an emergency and that the threat to the civilian control could be managed; that neither turned out to be true suggests that in spite of the sometimes-blithe assertions to the contrary, these limitations represent real tradeoffs which are unavoidable with a professional, all-volunteer force. Indeed, the original Gates Commission largely maintained that there were no real tradeoffs to an all-volunteer force, a position that seems optimistic at best given current trends. Consequently, given the mounting evidence for many of the same limitations in the current All-Volunteer Force as in the past Roman one, it is past time for a debate about whether the current recruitment system still fits America’s best domestic and strategic interests.

BOTH ROME and the United States were impelled by similar concerns to shift from conscription to a volunteer force. The first concern, of course, was domestic: the increasingly politically intolerable burden of service for the citizenry had made finding alternatives to continued conscription imperative for politicians. In the United States, the crucial context for the Gates Commission and the subsequent shift to the All-Volunteer Force was draft resistance as a result of the Vietnam War.

The Roman All-Volunteer Force also emerged in the context of increasing popular resistance to the burden of military service in increasingly remote campaigns. Scipio Aemilianus took the first volunteer Roman army with him to Spain in 134 BC as reinforcements for the Numantine War. He had enrolled a force of volunteers apparently because of political resistance to the dilectus (the Roman draft) which had arisen out of the protracted nature of Roman military operations in Spain. The practice of enrolling volunteers, often from among the poorer citizens, rather than drafting farmers, would become permanent in 107 BC when Gaius Marius, in part facing a shortage of eligible draftees—likely from draft-resistance rather than an actual manpower shortage as the Roman conscription system had few mechanisms for true compulsion—enlisted volunteers for the war against Jugurtha, a Numidian prince in North Africa.

There was a broader economic dimension to political resistance to the draft in both cases. While the Gates Commission report avoids dwelling on the anti-war movement (though for all involved this was the well-understood background to the report), it does give considerable prominence to the economic cost of service. Noting that “conscription is a tax” because the low wages of compelled service meant that “draftees and draft-induced enlistees [were] bearing a tax burden over three times that of comparable citizens,” the Gates Commission recommended that the All-Volunteer Force, while costing more to the federal budget, would represent an overall reduction on the economic burden of service on the citizenry.

This line of thinking, that conscription meant that the economic burden of service fell unfairly, would have been perfectly at home in the Roman Republic of the second century BC as the foundations of the later Roman professional army were beginning to form. In 133 BC, just one year after Scipio Aemilianus’ successful experiment with enlisting an all-volunteer army, Tiberius Gracchus, a tribune of the plebs, proposed a sweeping land reform package. Tiberius’ reforms were motivated by an apparent manpower shortage. This shortage was caused, the Romans thought, by the fact that the Italian peasantry had been crushed by the burden of repeated military service. Long campaigns had led them to lose their farms which, because there was a wealth requirement to serve as Roman soldiers needed to supply their own equipment, led in turn to them being both poor and ineligible for the draft. Modern scholars still debate the degree to which this manpower shortage was real, as the Roman census was self-reported such that draft resistance might show up as demographic or economic decline. Nevertheless, it was clearly a hot-button issue at the time: Tiberius’ reform package was passed even over the near-united opposition of the Senate, whereupon the senators murdered him for his troubles, inaugurating a spiral of violence which would eventually culminate in the collapse of the Republic itself.

The second part of this concern over the burden of military service and resistance to it was the need to adapt to a changing security situation more focused on holding on to what had been gained, what we may call “frontier maintenance,” and less focused on expansion or wars with peer competitors. In the Roman case, the Roman Republic’s system of conscription in the third and second centuries served it extraordinarily well, enabling Rome to out-mobilize its competitors at a relatively low cost to the limited Roman treasury (though with a somewhat greater cost to Roman citizens, as many costs were devolved down to private individuals). But, as the resistance to the dilectus for both Spain in 133 BC and North Africa in 107 BC showed, the Romans were reluctant to support continued conscription for increasingly long, distant, and unprofitable wars. Earlier wars against Pyrrhus of Epirus (280–275 BC) and Carthage (264–241 BC, 218–201 BC) had demanded tremendous sacrifice, but they had been local wars with peer competitors that posed a clear potential danger to the Roman state. Later wars against Macedon (200–196 BC, 172–168 BC, 150–148 BC) and the Seleucid Empire (192–188 BC) had been less clearly tethered to immediate Roman security concerns, but had at least been profitable, giving soldiers and senators alike the opportunity to loot the vast wealth of the eastern Mediterranean.

But the long wars in Spain and North Africa, waged merely to hold on to and consolidate earlier territorial gains outside of Italy, were both only loosely tethered to Roman security concerns and offered fewer (though by no means none) opportunities for soldiers to enrich themselves. At the same time, the Romans were unwilling to give up the vast empire they had acquired, the tribute of which was by that time already sufficient for most taxes in Italy to have been discontinued. Given that set of incentives, which would only intensify as Rome turned almost fully from conquest to holding the frontier under Augustus (who was, in turn, responsible for the true professionalization of the legions, turning them into standing units of long-service professionals), the shift to an all-volunteer professional force seems almost overdetermined.

Interestingly, the Romans were not the only empire at this time which, when faced with a security profile that had shifted from the conquest of peer competitors to the consolidation and maintenance of gains, moved from a mass conscript army to a more permanent, long-service force. As the Han Dynasty (202 BC to 221 AD) emerged as the final winner of the Warring States period (and the brief rule of the Qin Dynasty, 221–206 BC), it steadily moved away from universal conscription in order to more effectively guard its frontiers, particularly on the steppe. While the Han initially had a military system requiring all males between the ages of twenty-three and fifty-six to perform two years of military service (one in their home province, one abroad), early in the first century AD, this system was discontinued in favor of a fully professional military deployed primarily to the frontiers.