Paradoxical Geniuses: “Let us burn the ships”

In 1519, Hernán Cortés landed 500 men in 11 ships on the coast of the Yucatan, knowing that he was openly disobeying the governor of Cuba and that he was facing unknown numbers of potential enemies in an unknown situation. Regardless of the moral implications, what happened next was strategically extraordinary: he and his men formed a local alliance, and despite having to beat a desperate retreat on La Noche Triste, they conquered the second largest empire in the New World. As the expeditionary force landed, Cortés made a tactically irrational decision: he scuttled all but one of his ships. In doing so, he hamstrung his own maneuverability, scouting, and communication and supply lines, but he gained one incredible advantage: the complete commitment of his men to the mission, for as Cortés himself said, “If we are going home, we are going in our foes’ ships.” This strategic choice highlights the difference between logic and economists’ concept of “rationality,” in that illogical destruction of one’s own powerful and expensive tools creates a credible commitment that can overcome a serious problem in warfare, that of desertion or cowardice. While Cortés certainly increased the risk to his own life and that of his men, the powerful psychology of being trapped by necessity brought out the very best of the fighting spirit in his men, leading to his dramatic victory.

This episode is certainly not unique in the history of warfare, and was not only enacted by leaders as a method of ensuring commitment, but actually underlay the seemingly crazy (or at least overly risky) cultural practices of several ancient groups. The pervasiveness of these psychological strategies shows that, whether each case was because of a genius decision or an accident of history, they conferred a substantial advantage to their practitioners. (If you are interested in how rational choices are revealed in the history of warfare, please also feel free to read about hostage exchanges and ransoming practices from an earlier blog!) I have collected some of the most interesting examples that I know of, but the following is certainly not an exhaustive list and I encourage other episodes to be mentioned in the comments:

  • Julian the Apostate
    • Julian the Apostate is most famous for his attempt to reverse Constantine the Great’s Christianization of the Roman Empire, but he was also an ambitious general whose audacity gained him an incredible victory over Germanic invaders against steep odds. He wanted to reverse the stagnation of Roman interests on the Eastern front, where the Sasanian empire had been challenging the Roman army since the mid-3rd century. Having gathered an overwhelming force, he marched to the Euphrates river, took ships from there to the Sasanian capital, while the Sasanians used slash-and-burn tactics to slow his advance. When Julian found the capital (Ctesiphon) undefended, he worried that his men would want to loot the capital and return homeward, continuing the status quo of raiding and retreating. To prevent this, in a move much like that of Cortés, he set fire to his ships and forced his men to press on. In his case, this did not end with stunning victory; Julian overextended his front, was killed, and lost the campaign. Julian’s death shows the very real risks involved in this bold strategy.
  • Julius Caesar
    • Julian may have taken his cue from a vaunted Roman historical figure. Dramatized perfectly by HBO, the great Roman general and statesman Julius Caesar made huge gamble by taking on the might of the Roman Senate. Despite being heavily outnumbered (over 2 to 1 on foot and as much as 5 to 1 in cavalry), Caesar committed to a decisive battle against his rival Pompey in Greece. While Pompey’s troops had the option of retreating, Caesar relied on the fact that his legionaries had their backs to the Mediterranean, effectively trapping them and giving them no opportunity to rout. While Caesar also tactically out-thought Pompey (he used cunning deployment of reserves to stymie a cavalry charge and break Pompey’s left flank), the key to his victory was that Pompey’s numerically superior force ran first; Pompey met his grisly end shortly thereafter in Egypt, and Caesar went on to gain power over all of Rome.
  • Teutones
    • The impact of the Teutones on the Roman cultural memory proved so enduring that Teutonic is used today to refer to Germanic peoples, despite the fact that the Teutones themselves were of unknown linguistic origin (they could very well have been Celtic). The Teutones and their allies, the Cimbri, smashed Roman armies which were better trained and equipped multiple times in a row; later Roman authors said they were possessed by the Furor Teutonicus, as they seemed to posses an irrational lack of fear, never fleeing before the enemy. Like many Celtic and Germanic peoples of Northern Europe, the Teutones exhibited a peculiar cultural practice to give an incentive to their men in battle: all of the tribe’s women, children, and supplies were drawn up on wagons behind the men before battles, where the women would take up axes to kill any man who attempted to flee. In doing so, they solved the collective action problem which plagued ancient armies in which a few men running could quickly turn into a rout. If you ran, not only would you die, but your wife and children would as well, and this psychological edge allowed a roving tribe to place the powerful Roman empire in jeopardy for a decade.
  • The Persian emperors
    • The earliest recorded example of paradoxical risk as a battle custom is the Persian imperial practice of bringing the women, children, and treasure of the emperor and noble families to the war-camp. This seems like a needless and reckless risk, as it would turn a defeat into a disaster in the loss of family and fortune. However, this case is comparable to that of the Teutones, in that it demonstrated the credible commitment of the emperor and nobles to victory, and used this raising of the stakes to incentivize bravery. While the Persians did conquer much of the known world under the nearly mythical leadership of Cyrus the Great, this strategy backfired for the last Achaemenid Persian emperor: when Darius III confronted Alexander the Great at Issus, Alexander’s crack hypaspist troops routed Darius’ flank as well as Darius himself! The imperial family and a great hoard of silver fell into Alexander’s hands, and he would go on to conquer the entirety of the Persian empire.

These examples show the diversity of cultural and personal illustrations of the rational choice theory and psychological warfare that typified some of the most successful military leaders and societies. As the Roman military writer Vegetius stated, “an adversary is more hurt by desertion than slaughter.” Creating unity of purpose is by no means an easy task, and balancing the threat of death by frontline combat with the threat of death during a rout was a problem that plagued leaders from the earliest recorded histories forward (in ancient Greek battles, there were few casualties on the line of battle and the majority of casualties took place during flight from the battlefield. This made the game theoretical choice for each soldier an interesting balance of possibly dying on the line but living if ONLY he ran away, but having a much higher risk of death if a critical mass of troops ran away–perhaps this will be fodder for a future post?). This was a salient and even vital issue for leaders to overcome, and despite the high risks that led to the fall of both Julian and Darius, forcing credible commitment to battle is a fascinating strategy with good historical support for its success. The modern implications of credible commitment problems range from wedding rings to climate accords, but very few modern practices utilize the “illogical rationality” of intentional destruction of secondary options. I continue to wonder what genius, or what society, will come up with a novel application of this concept, and I look forward to seeing the results.

P.S.–thanks to Keith Kallmes for the idea for this article and for helping to write it. Truly, it is his economic background that leads to many of these historical questions about rational choice and human ingenuity in the face of adversity.

How to take over Syria, Roman edition

While Trump’s decision to bomb a Syrian airfield in response to use of chemical weapons by the Syrian government got the lion’s share of the press attention about American involvement in Syria (probably because of the contrast with Obama’s preference for diplomacy despite his “red line” threat), the more important strategic operations have not been discussed as fully. Building upon the successful establishment of two airfields last year, the US has expanded or established bases at crucial locations and begun to attack key targets in the northern part of Syria that show an excellent understanding of the topography and logistics of the region. These developments may be the linchpin in choking off traffic and crippling supply and movement of ISIL, and should contribute to the long-term goal of securing Hasakah and Raqqah provinces. What is interesting in all of this, perhaps due to the historical expertise of National Security Adviser H.R. McMaster, is that this logistical focus mimics the attack routes that were vital to invasions of the area from Alexander the Great down to Julian the Apostate.

The Euphrates River as an ancient supply highway

In the era of Alexander the Great, supply and communication were important constraints on military action; the logistics of his march through Syria are extremely well described by Donald Engels. Essentially, because of the lack of water sources in surrounding areas, the rough Taurus Mountains to the north and Arabian Desert to the south, and the provisions and easy transport supplied by it, the Euphrates River was a common “highway” for military movement in antiquity. Controlling and utilizing it was essential to control of the trade and military actions between the Mediterranean coast and Mesopotamia. In his defense against Alexander, Darius III kept his army on the Euphrates, and Alexander surprised him by crossing northern Mesopotamia to follow the Tigris River (near Mosul, which ISIL also recognized as vital) instead. However, almost every major invasion of the area from the west has gone through what is now southeastern Turkey to reach the headwaters of the Euphrates, including those of Trajan, Septimius Severus, and Julian the Apostate. Crassus reaped the gruesome rewards of avoiding the Taurus/Euphrates route.

The Euphrates valley was important not only as a military route, but also as a source of agricultural income and a crucial portion of the early Silk Road. Therefore, the nation that controlled the northern Euphrates valley could finance their military through control of trade and taxation (which Zenobia’s husband used to assert his own quasi-independence from a city that ISIL has ironically destroyed), a fact that has changed only in the economic transition from agricultural production to petroleum extraction. Now, ISIL not only taxes and sells oil to support its endeavors, but it knew from the outset to seize strategic locations on the route and even wanted to use the Euphrates river as its logo!

The mountains north of the Euphrates

The famous historian and general, Xenophon, was part of an army that followed the Euphrates down to a fateful battle at Cunaxa, and his retreat through the Taurus Mountains and ancient Armenia involved encounters with natives who were extremely capable in skirmishing on mountainous terrain. Both Xenophon and Mark Antony learned how difficult this route was, and the successful Kurdish defense of the Sinjar mountains and victories in the mountains of northeastern Syria using small arms and mobile forces while conceding villages is reminiscent of these ancient raiding methods. Though bombing obviously differs in technology and methods from ancient infantry, it also involves avoiding direct battle in order to destroy resources and harass enemy armies in motion, and so the American strategies based on assaults from the Rmeilan and Incirlik airfields over the past year have used the same attrition tactics to wear down ISIL strongholds.

What comes next?

If ancient campaigns can tell us anything, it may be that the US is transitioning from bombing from afar to more direct assaults on the cities, roads, and resources of ISIL along the northern Euphrates. The US still holds bases in northwestern Syria, defending the western flank of Kurdish-controlled territory and providing a buffer to Turkey (which, along with Turkish efforts to stop individual penetration of the border, should mitigate ISIL recruitment and international travel). Now that it has augmented this by creating bases that choke off routes to the headwaters of the Euphrates and allow closer engagement with ISIL since January, the US seems to be poised to contain ISIL attacks with greater alacrity and support Kurdish ground assaults on the ISIL capital of Raqqa. The escalation may be as support in the race to Raqqa and to take advantage of victories in eastern half of the campaign in Mosul, and comparison to the campaigns cited above would indicate that the US and Kurds are moving much slower than ancient campaigns, but using the same routes, attacking targets in similar ways, and with the same respect for topography and logistics.