The word ‘Byzantine’ has come to denote political intrigue of treacherous complexity. Thus, it might be thought that a Byzantine grand strategy would be something to avoid like the plague; a nightmarish tangle of ill-conceived and contradictory policies that is guaranteed to produce catastrophe [sound familiar?]. In fact, the empire from which the term derives was one of the longest surviving empires in history. Surely they must have done something right.
Indeed, as Edward Luttwak argues in his new book, The Grand Strategy of the Byzantine Empire, Byzantine history provides an excellent example of a grand strategy that utilized all instruments of state power to maximum effect.
Strategy is an imperative for the poor and the weak. Compared to the united Roman Empire of centuries past, Byzantium was both. When it decided to wage war, the ancient Roman Empire was able to combine well-trained military forces raised from its huge manpower reserves with sheer warlike determination to literally grind its enemies into dust, often abandoning strategic and tactical subtlety to gain victory through simple attrition; a high-cost but low-risk strategy guaranteed to produce success for anyone able to foot the bill. Not so the Byzantine Empire, which suffered from a chronic shortage of combat-ready troops and a disadvantaged geography that left it surrounded by enemies, with no easily defensible frontiers or a secure “homeland” territory. And yet, the Byzantine Empire survived nearly a millennium longer than its Western ancestor. How? With a grand strategy attuned to its situation.
Byzantium’s situation was one of endless war, if not with a particular enemy then with others that would follow it. On its European frontier, the Empire faced the recurring onslaughts of migrating steppe peoples, beginning with the Huns. No sooner would one be defeated then another would appear behind it as the migratory pressures of central Asia pushed nomadic populations westward out of the steppe like clockwork. On the eastern frontier was a perpetual border conflict with Sassanid Persia that would occasionally escalate into full-scale war. The Sassanid threat would be replaced by Islam with its constant ghazi raiding and annual jihadi invasions, first by the Arabs and then by the converted Turkic peoples. And then there were the peripheral threats to the West as the rest of Christendom picked off remaining Byzantine enclaves on the opposite shore of the Adriatic and beyond. Thus, for the Byzantine Empire, decisive victory of any sort was impossible. Had it waged all-out wars of annihilation like its Roman predecessor it would have rapidly exhausted itself into oblivion. Instead,
They [the Byzantines]…learned to view their enemies of the moment with a distinct element of ambivalence, evaluating them not only as immediate threats that had to be countered and possibly fought very hard, but also as possible future allies. That made attrition tactics inappropriate at the strategic level, as well as costly. (p. 284)
Since it was impossible for the Empire to defeat every one of its enemies militarily, diplomacy became the primary instrument of strategy:
The Byzantines continuously relied on deterrence – any power confronting other powers must do so continuously, if only tacitly – and they routinely paid off their enemies. But they did much more than that, using all possible tools of persuasion to recruit allies, fragment hostile alliances, subvert unfriendly rulers, and in the case of the Magyars, even divert entire migrating nations from their path. For the Romans of the Republic and the undivided empire, as for most great powers until modern days, military force was the primary tool of statecraft, with persuasion a secondary complement. For the Byzantine Empire it was mostly the other way around. Indeed, that shift of emphasis from force to diplomacy is one way of differentiating Rome from Byzantium, between the end of Late Roman history in the east, and the beginning of Byzantine history. (p. 112)
Those few instances when the Empire did attempt to completely vanquish an enemy usually serve to illustrate the ruinous consequences of such endeavors. During Justinian’s campaign to reconquer the former Roman territories in the west, Vandal power in Africa and Gothic power in Italy was destroyed rather than co-opted, saddling the Empire with the enormous expense of maintaining the newly conquered provinces. Much wiser to pursue limited objectives that leave the enemy of today strong enough to be meaningful allies against the enemies of tomorrow.
On the military level, the Byzantines developed a way of warfare that conformed to the larger strategy. Just as decisive victory at the strategic level was impossible, so it was on the battlefield. Instead of equipping itself for battles of annihilation with armies based around heavy infantry, the Byzantines embraced a doctrine of “relational maneuver” which emphasized cavalry to supply the necessary mobility:
For the Romans, who believed in destroying enemies not wise enough to recognize the advantages of submission, the cutting and thrusting and besieging heavy infantry was the most important arm, because it could best achieve decisive results. By contrast … the Byzantines believed in containing but not destroying their enemies – potentially tomorrow’s allies. Therefore for them the cavalry was the most important arm because its engagements did not have to be decisive, but could instead end with a quick withdrawal, or a cautious pursuit that would leave both sides not too badly damaged. (p. 272-3)
In both offensive and defensive operations, Byzantine commanders were expected to avoid open battle with the enemy’s main body unless they had an overwhelming advantage; otherwise they could not afford the inevitably high casualties. Relational maneuver required information in order to identify enemy strengths to avoid and weaknesses to exploit. The Byzantine art of war could not exist without intelligence; spies to learn the enemy’s strategic intent, reconnaissance and patrols to locate forces once they were deployed in the field, and probing attacks to identify weaknesses in their battlefield disposition. Only when the Byzantine commander had sufficient information to make a decision could he risk his own forces. For a strong army, a meeting engagement is a welcome opportunity to destroy the enemy, but for the Byzantines it was a catastrophic failure.
Avoiding battle could not produce results quickly. Instead of disarming the enemy directly, the Byzantines had to gradually undercut the sources of their strength. This took time. When Basil II set out to destroy the Bulghars (another rare example of an absolutist objective, but a rational one: the Bulghars controlled the Danube which was the only defensible terrain the European frontier), he did not seek victory in a single campaign of decisive battle. He slowly chipped away at their power by retaking the fertile lands along the Danube river valley. The campaign took decades, but it succeeded.
Even when the empire was threatened with destruction the Byzantines did not conform to the pattern of war imposed on them by the enemy, instead using maneuver to rapidly shift the center of gravity back in their favor (a good illustration of RADM J.C. Wylie’s “power control” in action). In the early 7th century, the Sassanid emperor Khusrau II abandoned Persia’s traditionally limited border objectives and launched a campaign to conquer the entire Byzantine Empire. Over the next two decades, Byzantium suffered defeat after defeat, losing all of the Levant and most of Anatolia to the Persians and most of Europe to the Avars. By 624, the emperor Herakleios was left with Constantinople itself and a few scattered pieces of territory along the Aegean. With the Avars and Persian converging on Constantinople, Herakleios made a final, desperate gamble. He gathered the remnants of the Byzantine army together, left Constantinople to fend for itself, and drove rapidly across Anatolia, into the Caucuses, and down into Mesopotamia, into the very center of Sassanid power. Persia’s armies were scattered across the recent conquests, unable to defend the capital Ctesiphon. Seeing the Byzantines at their doorstep, Khusrau’s court rivals murdered him and made peace with Herakleios. When the Empire was on the verge of destruction, Herakleios took the only option he had left – deep, rapid maneuver – and the Empire survived another 800 years.
Byzantine grand strategy can be summarized as follows: pragmatic diplomacy to neutralize enemies and gain allies; subversion and bribery where possible to secure victory inexpensively; relational maneuver and asymmetrical warfare on the battlefield; all guided by the assumption of war without end “because as soon as one enemy is no more, another will surely take his place for all is constantly changing as rulers and nations rise and fall. Only the empire is eternal. (p. 417)” In Luttwak’s own words:
The genius of Byzantine grand strategy was to turn the very multiplicity of enemies to advantage, by employing diplomacy, deception, payoffs, and religious conversion to induce them to fight one another instead of fighting the empire. Only their firm self-image as the only defenders of the only true faith preserved their moral equilibrium. In the Byzantine scheme of things, military strength was subordinated to diplomacy instead of the other way around, and used mostly to contain, punish, or intimidate rather than to attack or defend in full force. (p. 415)
What can America learn from Byzantium? America is neither Rome nor Byzantium; it has the military strength to annihilate its enemies utterly, but it is unable to exercise that power because of its own legalistic moralism, its fear of contravening international norms of state behavior, the opposition of other major powers in the system, and the irregular nature of most of its enemies. Yet it continues to proclaim maximalist objectives (e.g. the eradication of terrorism) while abiding by the constraints that prevent it from reaching those objectives, gradually exhausting itself in a vain pursuit of final victory and the End of History. If America should learn one thing from Byzantium, it is that war is eternal; to exert strenuously against a particular enemy is only to hasten decline, for a new enemy is always on the horizon.