Three dozen silhouettes glided silently through the dense pine forests. The platoon’s tactical movement was flawless, executed according to doctrine and in a manner honed by countless repetitions in training. Dusk was settling over the border region the platoon’s battalion—part of the 173rd Airborne Brigade—had recently occupied. For weeks, geopolitical pressure had mounted after a series of hostile cross-border air incursions, unattributed drone overflights, acts of sabotage, and cyberattacks on communications infrastructure. A NATO member had invoked Article 4, and US forces forward deployed to reassure allies and deter further escalation. That deterrent was failing. The previous night, a border guard post had been destroyed by a long-range loitering munition launched from across the frontier. The attack left little room for debate in Brussels. By morning, Article 5 was invoked, and the Sky Soldiers of the 173rd Airborne were directed to prepare for possible contact along an exposed eastern corridor.
The platoon leader received orders to establish a patrol base roughly three kilometers from the demarcation line. The intent was simple: Consolidate the platoon, conduct maintenance, and prepare reconnaissance teams for forward observation along likely avenues of approach. The platoon leadership knew the US Army Ranger Handbook like the backs of their hands and had rehearsed the steps of patrol base occupation dozens of times to include execution at the Joint Multinational Training Center a few months ago. The soldiers could establish a patrol base with the same tactical excellence with which had moved through the forest. Even here, on NATO’s eastern frontier, the platoon’s standard operating procedure remained unchanged. The patrol base would be triangular. The perimeter would be oriented outward along interlocking fields of fire. Security priorities were unaltered, the internal layout unchanged, and at the apexes critical weapons evenly distributed. The patrol base would have passed scrutiny from even the toughest Ranger instructor at Camp Darby.
Under cover of darkness, the platoon’s soldiers moved into a thick patch of conifers and initiated occupation of their patrol base. They executed the process with textbook precision—establishing near-side and far-side security, clearing along the axis of advance, and taking up positions at the triangle’s three points. Weapons teams dug in, scraping shallow fighting positions into the frozen leaf litter. Riflemen unrolled their ponchos and began a silent rotation of weapons maintenance, personal hygiene, and rest. The RTO (radio telephone operator) and fire support noncommissioned officer set up the platoon’s command post near a fallen log, raising a camo net to help break up visual signatures. Not a white light flicked on. Not a word was spoken above a whisper.
The forest around them was colder than usual—a dry cold, the kind that traps heat against bodies no matter how well a soldier hides it. As the men worked, their movement warmed the earth beneath their boots. Their breath lingered in faint clouds that drifted between the trees. A single M240 barrel, still warm from earlier zeroing, radiated like a flare compared to the frigid air. None of it mattered to the naked eye. All of it mattered to an adversary hunting the platoon with thermal-equipped drones.
Across the border, a battalion-sized tactical group had been preparing its own rapid-reaction response since Article 5’s invocation. The enemy forces, well familiar with Western doctrine through years of observation and the lessons drawn from Ukraine, anticipated that US light infantry would occupy rest positions in predictable shapes. Their reconnaissance company launched three small quadcopters shortly after sunset. Each drone carried a commercial-grade thermal optics module purchased from a European reseller and modified for ruggedization. These were not exquisite military platforms; they were inexpensive, silent, and disposable—perfectly adequate for the task ahead.
The drones drifted through the treetops, flying low to avoid radar. Their operators watched the feed on ruggedized tablets from inside a hardened vehicle several kilometers away. At first, the screens showed a blank gradient of cold forest. Then, in one corner, faint warm spots appeared. The thermal feed sharpened as the drone descended. Three clusters of warmth arranged in an approximate triangle emerged from the haze. The drones hovered, zooming in until the outlines of men, stationary but clearly present, became apparent. A distinct central signature near a long horizontal shape indicated the platoon command post. Everything matched standard US patrol base diagrams, down to the spacing.
The drone team relayed coordinates to the battalion fire direction center. A battery of 152-millimeter self-propelled howitzers pivoted their tubes. Propellant charges were adjusted. The first fire mission was a three-round ranging sequence, its impacts walking toward the platoon’s location from several hundred meters out. In the forest, the platoon reacted instantly to the thunder of the first explosion, but the platoon leader hesitated to displace prematurely. Ranging shots were common in exercises. This was different terrain, a different context, yet doctrine demanded verification before uprooting the patrol base. He ordered the platoon to stand to but maintain positions. Seconds later, the drone operator saw men rising to their knees, heat signatures shifting. That confirmation was all the enemy required. The fire direction center sent the execute code for the full strike: a battalion fire-for-effect with airburst fusing. Artillery crews rammed shells into breeches and pulled firing lanyards in rapid succession. A ripple of muzzle flashes lit the distant horizon.
The rounds arrived in a violent cascade. Airburst explosions ripped through branches and detonated above the triangular perimeter, spraying red-hot shrapnel downward. The command post net collapsed in the first seconds as fragmentation shredded the camo fabric and tore through the log beneath it. The RTO fell instantly, his radio destroyed. A mortar team in one corner of the triangle took the brunt of the second volley. The team’s fighting position, shallow and hastily dug, offered little protection from overhead fire. The soldiers scrambled from their positions, but their movement only intensified their thermal signatures. The drones tracked the chaos, cueing adjustments to the fire mission. Fresh rounds landed along the platoon’s new axis of withdrawal, bracketing escape routes. A final series of strikes sent splintered trunks crashing to the ground as fire swept across the forest floor.
Within minutes, the perfectly established patrol base was erased and the platoon that had occupied it ceased to exist as a coherent fighting element. Survivors crawled through burning debris, dragging casualties toward a shallow ravine that offered some protection. The triangular shape that had once represented disciplined security had instead concentrated the soldier’s heat signatures into the most detectable form imaginable. The enemy did not need to see them visually. The forest told the story on their behalf.
Hours later, after the barrage ended and Russian drones retreated, a small NATO quick reaction element reached the battered survivors. What the responding soldiers found was not a unit defeated in a fair fight, but one undone by a collision between legacy doctrine and new realities. The platoon had done everything right, by the handbook. The US soldiers had executed every step with care and professionalism. Yet the very doctrine that had guided them had betrayed them. In the age of thermal transparency, the triangular patrol base had become less a defensive sanctuary than a predictable target.
The next morning, as NATO command reviewed the attack, a single line from the operations report captured the lesson with brutal clarity: “Enemy drones detected warm signatures in a triangular formation consistent with US doctrinal rest positions. Artillery exploited this pattern with precision.” And across the 173rd, battalion and brigade leaders began reevaluating every assumption about how their soldiers should hide, rest, and survive in a world where darkness no longer conceals, and doctrinal shapes have become liabilities.
For more than twenty years, US Army small-unit tactics have rested on the belief that disciplined fieldcraft, careful security at rest, and deliberate application of movement techniques and formations would allow units to survive in austere, uncertain terrain. The patrol base, often triangular because of its simple geometry for 360-degree security and easy internal control, is a doctrinal centerpiece that US Army infantry has long treated almost as sacred. Yet as the character of war evolves, as experienced by the platoon in the scenario described above (fictional, but wholly realistic), the assumptions underpinning these long-standing techniques are collapsing. The global proliferation of thermal imaging technology has fundamentally altered detectability on the modern battlefield, reshaping what it means to hide, to move, and to survive. Today, a doctrinal patrol base dug into a tree line does not disappear into darkness at all. It radiates like a beacon.
Thermal imaging has saturated the battlefield at every echelon. What was once a high-end capability reserved for advanced militaries and elite formations is now found in the hands of irregular fighters, criminal groups, and even lone individuals. Off-the-shelf long-wave infrared optics can be purchased online for a fraction of the cost of a rifle. Recreational hunters now wield sensors comparable to what US special operations forces fielded only a decade ago. State and nonstate actors alike equip drones, vehicles, and dismounted soldiers with thermal imagers as routinely as they carry radios. And in the most concerning evolution, thermal sensors are increasingly integrated into airborne and ground unmanned systems to include loitering munitions and first-person-view, strike-capable drones. Darkness, once the US military’s strategic ally, no longer provides refuge.
Traditional concealment depended on terrain, discipline, and camouflage. Each of these foundations is now eroded. Terrain, which once masked movement and protected bases, now often creates contrast that enhances detection. A soldier dug into the cold earth of a forest stands out not because of his shape, but because of his temperature relative to his surroundings. A triangular patrol base, with three predictable nodes of human heat, is not a clever geometric solution; it is a thermally obvious cluster recognizable from hundreds of meters. Noise and light discipline, long the bedrock of infantry professionalism, no longer compensates for thermal visibility. A silent unit still radiates: Warm weapons, the residual heat of recently fired brass, sweat evaporating off clothing, and boot prints in recently disturbed soil all glow to even modestly capable thermal devices. Visual camouflage, from face paint to ghillie suits, works primarily against the human eye rather than thermal sensors. Thin brush, nylon fabric, and wet vegetation offer little protection. In an age of omnipresent thermal surveillance, the disciplined soldier may still be tactically proficient, but no longer invisible even when attempting to employ thermal mitigating equipment.
Thermal integration across drones, vehicles, and dismounted personnel has created an environment in which forces can be detected, fixed, and targeted with unprecedented ease. Thermal-equipped drones represent the most transformative change. A quadcopter carrying an inexpensive thermal module can scan an entire company-sized area in minutes, pausing silently over the canopy while detecting heat signatures through natural gaps. Algorithms will soon assist operators by highlighting anomalous clusters of warmth while loitering munitions home in on thermal contrast autonomously. A patrol base that might once have survived by minimizing noise now faces persistent surveillance from above, regardless of the time of day.
Meanwhile, ground vehicles mount high-quality thermal sights that allow them to scan wide arcs and identify hidden dismounts, recently dug positions, or warm engine blocks even when visually obscured. When paired with accurate long-range fire systems, these sensors allow mechanized elements to dominate movement corridors at night; when employed by adversaries with peer capabilities, this represents an inversion of the historical US advantage. Even irregular fighters now carry thermal scopes and monoculars. A single individual with a handheld device can detect and compromise a squad-sized patrol base from distances that once required a reconnaissance platoon.
Collectively, these changes compress decision space for commanders. Tactical surprise at night, long a defining American advantage, has been severely weakened. Enemy forces now observe infiltration routes, assembly areas, and supply nodes with thermal persistence. A unit attempting to rest in a doctrinal patrol base has only a short window before detection, and once located, it becomes vulnerable to rapid fires. Contemporary conflicts demonstrate kill chains in which a thermal-equipped drone identifies a heat cluster, directs artillery within minutes, and then observes displacement to cue a follow-on strike. Loitering munitions stalk the warm signatures of survivors and equipment long after the initial barrage. The once safe logic of stopping, consolidating, and reorganizing in a patrol base is now a liability.
The implications for Special Forces and unconventional warfare are equally profound. Guerrilla forces have historically relied on dispersed, clandestine camps concealed in rough terrain. Thermals erode the protective value of these sanctuaries. Campfires, generators, vehicles, and even human bodies generate signatures detectable from great distances. Unconventional warfare practitioners and advisors must now teach partner forces not simply to hide, but to manage their heat emissions, disperse their assets, and remain ready to displace rapidly. Special operations forces would be wise to apply humility to capture and apply the hard-earned battlefield lessons of their Ukrainian counterparts. Signature control—whether thermal, electromagnetic, or acoustic—has become more important than classical visual stealth and the widening application of exquisite technologies enjoyed by special operations forces risks undermining the criticality of surprise. It will be true that in many environments, survival belongs not to the best camouflaged unit but to the coldest one.
These realities call into question whether the triangular patrol base, at least as traditionally practiced, retains operational relevance. The geometry itself is not the issue; the problem is that the patrol base embodies assumptions about visibility that no longer hold. A fixed position of predictable shape, occupied by warm bodies and equipment, cannot avoid detection by an enemy with even modest thermal capability. The answer is not to abandon security at rest, but to reconceptualize it. Patrol bases must become smaller, more dispersed, less thermally dense, and more ephemeral. Units may rest in micro-nodes rather than single geometric shapes. They may bed down along terrain that generates thermal clutter such as rocks, watercourses, or urban rubble rather than under trees. They may need to embrace cold bivouacs that prohibit stoves, warming layers, or activities that generate heat. And increasingly, they may rest while slowly moving through thermally complex terrain rather than stopping altogether. Deception, too, will become essential. Thermal decoys, artificially heated objects, or chemical warmers can draw enemy attention away from actual positions, just as visual decoys once confused optical reconnaissance.
To survive and win in a thermally compromised environment, the US Army must adapt in several ways. Doctrine should explicitly acknowledge thermal detection as a baseline condition rather than an occasional threat. Field manuals should incorporate thermal signature management in the same way earlier generations emphasized noise and light discipline. Units must receive equipment designed to reduce their thermal contrast, including multispectral camouflage nets, thermal blankets for personnel and equipment, active cooling liners, and low-signature stoves and heaters. Training must incorporate opposing forces equipped with thermal detection capability as a matter of routine, not exception, so that soldiers learn through experience how their actions appear to modern sensors.
The Army must also invest heavily in counterthermal reconnaissance. Dominating the night once meant dominating the visual spectrum. Today, it requires degrading enemy sensors through obscuration, jamming, and aggressive counterdrone tactics. Small units should maintain their own drone patrols to clear the airspace above them, while higher echelons develop capabilities to detect, track, and disrupt thermal-equipped reconnaissance systems. Finally, basing across all echelons, from squad rest plans to division support areas, must become smaller, more mobile, more dispersed, and more deceptive. The concept of a large, semipermanent support area radiating heat and activity is incompatible with modern precision fires cued by persistent thermal reconnaissance.
Darkness is no longer a natural ally, but it can become an artificial one if armies learn to deny thermal visibility. Smoke, obscurants, thermal-jamming devices, and deliberate manipulation of the environment can recreate the sanctuary that night used to provide. The key is accepting that the battlefield is now heat transparent by default and units at all echelons must act accordingly. The triangular patrol base is more than a tactic; it is a symbol of a bygone era when soldiers could trust terrain and darkness to hide them. Thermal imaging has ended that era. The forces that prevail in future conflicts will be those that outmaneuver not just enemy formations but enemy sensors. In a world where everything warm is visible and everything visible is vulnerable, survival and success will belong to units that embrace constant mobility, disciplined signature control, and aggressive counterreconnaissance, and are armed with doctrine built for the heat-transparent battlespace.
Major Charlie Phelps is a Special Forces officer and currently serves as a company commander in 10th Special Forces Group (Airborne).
Master Sergeant Benny Jenness is a Special Forces noncommissioned officer and recently completed service as a team sergeant in 10th Special Forces Group (Airborne).
The views expressed are those of the authors and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
Image credit: Spc. Cambrie Cannon, US Army