The increasing use of drones on the modern battlefield has sparked a great debate about their impact on the ever-changing character of warfare. Whether framed as evolutionary drivers of that change or revolutionary disruptors, however, security professionals should be cautious in forecasting—not least because, to date, we have not seen a true meeting engagement of drone-enabled conventional forces in large-scale offensive operations. Rather, what we have witnessed are blood-soaked previews of what may come next, written across the labyrinths of trenches in Ukraine and the battlefields of the Middle East.
Amid the ongoing Russo-Ukrainian conflict, drones are often spoken of as if they will usher in a military revolution because of the massive casualties they are causing on the modern battlefield. Yet neither belligerent has used traditional airpower to any great extent, and some of drones’ effectiveness may be due to Russia’s poor ability to conduct fluid maneuver. The increasingly static battlefield has also created conditions particularly favorable to drones: relatively protected operating areas, established sensor networks, prepared positions, and targets repeatedly forced through observable avenues of approach. In the current US-Iranian conflict, mounting attacks on American bases are a cause for concern; however, this too is far different from the kind of large-scale ground combat that would truly test how drone-enabled conventional formations fight one another while maneuvering under fire.
Today, there is also a slew of writing that encourages Taiwan to rely heavily on drones to mount a “hellscape” defense of its territory against a potential Chinese threat. As we pause to consider the implications of drones in this theater, we should reflect on the harsh historical lessons about introducing novel military technology. Military history repeatedly warns us that possessing a potentially revolutionary weapon and knowing how to wage war with it are two very different things.
In the fourteenth century, the English longbow was among the most lethal battlefield technologies that existed in Europe. At the battles of Crécy in 1346 and Agincourt in 1415, disciplined longbow archers shattered French knights and reshaped much of the character of medieval warfare. Yet only thirty two years before Crécy, in 1314, English longbowmen carried essentially the same killing technology onto the field at the Battle of Bannockburn and suffered a catastrophic defeat.
The difference in outcomes was not the weapon. Rather, it was the system built around it.
That distinction should haunt military planners today, particularly those seeking to defend Taiwan and deter Chinese aggression. Possessing vast numbers of drones means little if they cannot be wielded properly or survive long enough to be unleashed. If drones are to strengthen deterrence in the Taiwan Strait, the challenge is not simply to field them, but to build the institutions, training, doctrine, protection, and combined arms system capable of keeping them in the fight and translating their lethality into battlefield decision.
The Longbow at Crécy and Agincourt
The English longbow was a brutally simple weapons system composed of wood, sinew, and muscle-fueled firepower. Typically crafted from yew trees, the bow could store a tremendous amount of energy when drawn, often requiring a pull of 100–160 pounds. But the weapon was only as formidable as the human being wielding it. English archers trained from an early age, developing the strength and skill required to repeatedly draw these enormous bows through years of practice that could leave their skeletons permanently altered.
In combat, a skilled bowman could unleash six to ten arrows a minute, sending shafts over two hundred yards and delivering lethal force well beyond the reach of crossbows. When properly fielded, longbow units could unleash a system of massed fire capable of shattering cavalry or infantry assaults. At close range, hardened arrowheads could penetrate mail and armor, maim horses, and shred apart tightly packed formations. Knights who had spent lifetimes mastering mounted and close combat could be killed by men they might never reach.
When properly employed, thousands of longbowmen could transform muscle-powered weapons into massed battlefield firepower. This early version of steel rain could break the momentum of cavalry charges, disrupt formations, and establish the conditions for infantry and cavalry to finish the fight. But all that killing power depended on one unforgiving requirement: The archers had to be given the time, space, and protection necessary to unleash it. The same may prove true of the drones required for a hellscape defense that aims to turn the Taiwan Strait into a deadly barrier against invasion.
At Crécy in 1346 and Agincourt in 1415, the victorious English did not haphazardly employ the longbow. Rather, they developed a system around it. English commanders used terrain, obstacles, infantry, and field fortifications to give their archers the time and protection they needed to generate massed fire. In establishing these conditions, the authors of the longbow-enabled victories narrowed the battlefield, restricted French maneuver, and created deadly fields of fire through which the enemy had to advance.
It is important to note that the longbow did not win battles alone. Instead, it functioned as part of a larger, integrated tactical design. As with any novel weapon throughout military history, its lethality depended on an architecture built around it. It also required disciplined command structures capable of coordinating archers with infantry and mounted forces to be decisive in the field of battle. It required time, space, and security to generate massed and interlocking fields of fire. Longbowmen needed protected positions and other forces to prevent the enemy from closing with them.
At Crécy and Agincourt, the English had this architecture. The French, by contrast, guided by generations of chivalric traditions, attacked in a manner that fed their brave charges into the maelstrom of muscled-fueled firepower.
Crécy and Agincourt therefore offer a lesson that reaches far beyond the longbow: Battlefield lethality is not simply a property of the weapon. It is a product of the system that allows the weapon to survive, generate effects, and create opportunities for other forces to exploit. For Taiwan, the question is likewise not simply how many drones can be deployed on an island, but whether Taiwan and its partners can build the battlefield that enables those drones to be employed effectively when the battle commences.
Just as longbows had requirements in order to be put to deadly and effective use, drones need launch sites, communications, sensors, operators, logistics, and time to find and strike targets. For Taiwan’s defense, if China can destroy, disrupt, or compress that system before it can function, thousands of drones could be sidelined before they are ever afforded the chance to take the field.
The Longbow at Bannockburn
The English host that marched north in 1314 was one of the largest armies ever assembled in medieval Britain. Most estimates place King Edward II’s force at roughly eighteen to twenty thousand men, including around two thousand heavy cavalry, five to seven thousand longbowmen, and a large mass of infantry levies. Edward’s army was built for shock and momentum, centered on mounted knights who were expected to break enemy formations through direct assault. The longbowmen, though present in large numbers, were not yet doctrinally central to English tactics and were treated as a supporting arm rather than the core of the battle system. English command assumed that weight, speed, and cavalry shock would overwhelm Scottish resistance, just as they had in earlier campaigns. On paper, it was an army possessing nearly every advantage: numbers, firepower, and shock.
The Scottish commander, Robert the Bruce, commanded a far smaller force, likely between six and eight thousand men, composed primarily of spearmen organized into dense schiltrons, supported by a small contingent of five hundred light cavalry and minimal missile troops. Lacking the heavy knights and archers of the English, Bruce adopted a defensive-offensive hybrid strategy that relied on terrain, discipline, and cohesion rather than firepower.
The Scottish schiltrons were not static hedgehogs but mobile spear formations capable of advancing while maintaining defensive integrity and cohesion. Bruce deliberately chose narrow, marshy ground to restrict English maneuver and neutralize the English heavy cavalry.
As the battle scene was set, it appeared that the English possessed superior numbers, cavalry, and firepower. However, while they wielded the longbow, they lacked the playbook for victory.
When King Edward II’s large force traveled north to relieve Stirling Castle and suppress Robert the Bruce’s rebellion, its advantages on paper were offset by the fact that the English had yet to figure out the grammar of violence regarding how to best employ the longbow. Instead of setting the conditions to best employ the large units of longbow, the English pushed forward into the confined terrain that Robert the Bruce had chosen to rob them of tactical flexibility.
In the decisive phase of the battle, the Scots advanced in their deadly, mobile schiltrons against the English. To blunt this charge, the English deployed the archers on their unprotected, vulnerable right flank, lacking protection and support from man-made obstacles or terrain, as well as from any infantry. Robert the Bruce quickly exploited this mistake by sending a small force of light cavalry under Sir Robert Keith to attack the exposed archers. With no protective cover, supporting infantry, or room to retreat, the longbowmen were scattered in moments. Thousands of England’s most lethal weapons were effectively removed from the battle by a comparatively tiny force of Scottish horsemen. What remained was a congested mass of infantry and cavalry, trapped between marshland and advancing Scottish spears, unable to deploy, maneuver, or regain the initiative. The battlefield that should have showcased English numerical and technological superiority instead became a killing ground.
Bannockburn stands as a testament that the English defeat was not the result of inferior weapons, but of a failure to build a system that allowed superior weapons to function. It is important to understand that the battle was not a rejection of the longbow, but a warning that technology without protection, space, and integration can become a liability rather than an advantage.
That warning should echo ominously across the centuries and the Taiwan Strait. The danger is not simply that Taiwan might possess too few drones. It is that when the missiles begin to fall, communications fracture, launch sites burn, and operators are hunted, Taiwan could discover that masses of lethal weapons mean little if the battlefield no longer allows them to fight. Like the longbowmen at Bannockburn, they might not have the chance to affect the course of battle.
Drones and the New Grammar of Violence
The English forces’ defeat was in part due to their command system’s inability to translate capability into coordinated action under pressure. It takes time for soldiers and field commanders to learn a new grammar of violence whenever a novel weapons technology is introduced. Edward II did not possess a unified battlefield doctrine or shared understanding of how cavalry, infantry, and archers were supposed to fight together. While the English had the longbow, they had not yet learned how to wage war with it.
Similarly, today, while the drone certainly has deadly potential, it will take time to learn how best to unleash it on the battlefield. The armies of the drone age will have to learn through experimentation, adaptation, and inevitably blood. Bannockburn is a deadly reminder that sometimes battles are not lost when weapons fail, but rather, when military institutions fail to learn, coordinate, and adapt in real time.
To effectively unleash drones against enemy targets, military forces need time to build sensor networks and targeting chains, and drones and their operators need space and protection from conventional threats. Additionally, drones require protection from counterdrone systems and electronic warfare. Most importantly, their effective employment requires doctrine that connects drones to fires, movement, and decision-making. Like the longbow, the drone will likely become truly consequential only when it is integrated into a larger system of battle.
A drone operator, like a medieval archer, cannot fight while being overrun. He needs space to observe, cue, strike, and retask. If compressed, disrupted, or isolated, the drone, like the longbow, becomes irrelevant. This is the dark lesson of Bannockburn for the drone age: The enemy does not have to destroy your most lethal weapon, but only to destroy the conditions that permit it to be unleashed. He only has to hunt its operators, sever its networks, collapse the space around it, and rob it of the chance to kill. The weapon can remain perfectly lethal and still die upon the battlefield.
Weapons Do Not Write the Playbook
Bannockburn reminds us of a harsh truth that novel weapon technologies do not win battles or wars alone. The English longbow would only become decisive when battlefield commanders learned how to best employ it on the battlefield. Today, the accelerating proliferation of drone-enabled combat might follow a similar path. States that develop and equip their armies with drones in large numbers at first might not necessarily attain decisive victories. But rather, those who build the institutions, doctrine, tactics, and operational art may, for a time, possess an advantage.
Drones might, in fact, prove to be a decisive tool against a Chinese invasion of Taiwan, but only if drone forces can survive long enough to be unleashed. A drone force concentrated in a handful of exposed launch sites or airfields risks the same fate as the longbow units at Bannockburn. If drones are to play a vital role in Taiwan’s defense, they will require dispersal, concealment, redundancy, protected or hardened infrastructure, including subterranean support where feasible, and multiple launch points resilient to missile attack and electronic warfare. But protection cannot end with concrete, camouflage, and electronic defenses. Like the longbowmen at Bannockburn, drone operators and the networks that sustain them must also be protected from enemy infantry and special operations forces seeking to physically close with them and silence their weapons before they can be unleashed. In the end, the decisive factor will not be the drone alone, but the system built to keep it alive and in the fight.
The temptation in every age of innovation is to mistake a new weapon for a new way of war. The Battle of Bannockburn offers warnings against such presumptive forecasts. While a novel weapons technology can kill, it is rarely the silver bullet for achieving victory. Victory belongs to the military that learns fastest how to protect, integrate, and employ a weapon as part of a larger system of battle. Weapons may come with instruction manuals. However, they do not come with the playbook of victory. We would do well to remember that the future will not be won by machines alone, but by the humans who know how to wield them.
Antonio Salinas is an active duty US Army officer, professor of strategic intelligence at National Defense University, and a PhD student in the Department of History at Georgetown University. Salinas has twenty-eight years of military service in the US Marine Corps and Army as an infantry officer, an assistant professor in the Department of History at the US Military Academy, and a strategic intelligence officer, with operational experience in Afghanistan and Iraq. He is the author of Siren’s Song: The Allure of War, Boot Camp: The Making of a United States Marine, and Leaving War: From Afghanistan’s Pech Valley to Hadrian’s Wall.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
