Break In, Break Through, Break Out

Escaping the Modern Battlefield’s “No-Man’s-Land”

Maj. Gen. Thomas M. Feltey, US Army
Maj. Heath Rosendale, US Army
Maj. David Webb, US Army

Download the PDF (opens in a new window)

It was senseless to break down a door if there was no one to go through it.

—Georgii Samoilovich Isserson, The Evolution of Operational Art

Drones, ubiquitous sensors, and precision fires saturate the battlefields of Ukraine. So why, after years of war, has territorial control remained largely unchanged? Why do tactical victories fail to translate into strategic gains? Why do modern armies—equipped with unprecedented technology—find themselves fighting for meters rather than maneuvering for decisions?

The answer is uncomfortable: modern armies have rediscovered positional warfare but have forgotten how to escape it. It is not a failure of technology; rather, it is a failure of connection. Tactical action is no longer coherently linked to strategic purpose. At its core, this is a failure of operational art. Rather than prescribing a rigid solution, this article provides a cognitive framework for modern military professionals using the Allied victories of 1944 as a historical model for solving parallel operational challenges.

The Russo-Ukrainian war offers a stark illustration. On both sides, combat has compressed into a shallow 15–25 km zone. The result is eerily reminiscent of the “no-man’s-land” of World War I, the highly contested and dangerous stretch of terrain between opposing trenches. For the US Army—designed to seize the initiative and impose its will through offensive action—the question is not how to dominate this new no-man’s-land but how to overcome it.

Thankfully, history offers a parallel solution, but not one we instinctively reach for. Whereas technology matters, it is not just a faster platform, better sensor, or longer-range munition that is required. It is a warfighting framework that reconnects action throughout the depth and restores maneuver to the battlefield. It is worth noting that in this framework, infantry-centric combined-arms formations break into an area of operation, establishing a foothold. Armored combined-arms formations, supported by sufficient infantry forces, break through the enemy’s defensive depth. Finally, armored-centric combined-arms formations break out into the enemy’s deep area, successfully linking tactics to strategy through operational art. It is important to note that joint airpower continues to serve as the operational connective tissue throughout the framework, driving the transition from initial break-in through the breakthrough, and into the breakout. Although not codified in US Army doctrine, the legacy concepts of break in, break through, break out —long utilized by allied militaries—translate directly to the modern doctrinal sequence of forcible entry, penetration, and exploitation.

Operational Art

By the end of World War I, evolving tactics broke the deadlock of positional warfare. The Allies regained the ability to maneuver—and with it, the ability to decide the war. In the interwar years, military thinkers sought to understand and replicate that transformation, determined to ensure that future conflicts would not devolve into static, attritional stalemates. Some of the most consequential ideas emerged from the Soviet Union.

Soviet theorists, notably Vladimir Triandafillov and Mikhail Tukhachevsky, developed the theory of deep operations.¹ This framework emphasized the destruction, suppression, and dislocation of enemy forces not just at the tactical edge but throughout the entire depth of the battlefield. The key to this theory was exploiting tactical success by penetrating deep into the enemy’s strategic area. To describe this connective tissue, they introduced a new concept—the operational level of war.

A Soviet brigade commander, Georgii Isserson, expanded on this new term in his seminal 1936 work, The Evolution of Operational Art, in which he described “how to link separate, tactically independent combat efforts in space along a front and in time, i.e. throughout the depths, in order to achieve the general aim.”² In other words, operational art ensures that tactical actions are not independent of each other.

The US military adopted this intellectual framework and continues to use it nearly a century later, highlighting not only the enduring problem but the immense amount of thought theorists and practitioners have put into it. Those before us understood that operational art is not a checklist, but a way of thinking—one designed to overcome the fallacy of viewing the entirety of a war as simply the sum of its individual parts. Unfortunately, several aspects of the modern operational environment have hampered Russia and Ukraine’s ability to overcome this logical fallacy.

Modern Challenges

The modern battlefield in Ukraine has largely devolved into defensive operations. Offensive action, when it occurs, is often episodic and ill-suited to the realities of the contemporary operational environment. Persistent surveillance, drones, layered obstacles, long-range precision fires, and the interdiction of logistical nodes challenge the ability to mass combat power. Recent conflicts outside Ukraine do however suggest that the devolution into defensive operations is not necessarily inevitable, warning us against overinterpreting current trends as permanent blueprints for future conflicts.

These challenges are formidable but not insurmountable. Notably, the Ukrainians achieved operational surprise in 2024, penetrating into Kursk, Russia.³ This offensive employed a combined-arms approach, overcoming the transparent battlefield by degrading Russian intelligence, surveillance, and reconnaissance; employing deception and operational security; utilizing electromagnetic warfare; and identifying weak points in the obstacle belt. But success at the point of penetration is not success in depth. Lacking sufficient mass—particularly armored forces capable of sustaining momentum—Ukrainian forces were unable to transition from penetration to exploitation.

This dynamic is not unique to one side or a single sector. In late 2025, Russia seized the strategic cities of Pokrovsk and Myrnohrad, but it has been unable to capitalize on this success, with no significant advances westward in nearly six months.⁴ These instances indicate that destruction is achievable, but decision remains elusive—an operational problem, not a tactical one. The result is familiar: forces can break in but not break through or break out. While modern conflicts like the war in Ukraine illustrate these new dynamics, this three-phase framework is not theater-specific; rather, it offers a globally applicable model for neutralizing prepared defenses in any future conflict to achieve operational and strategic objectives (see figure).

Break In

The break-in is a modern joint forcible entry operation—designed to enter a system that can see, target, and destroy you before you can mass combat power. It is not simply about gaining access but about seizing and holding a lodgment under fire—creating the conditions for movement, maneuver, and follow-on operations. The break-in is a decisive point in an operation.

Historically, this task has fallen to infantry. Amphibious, airborne, and air assault forces possess the capability and adaptability to operate in restricted terrain. Their role is not to achieve decision, but to make it possible—to secure a foothold, enable the flow of combat power, and deny the enemy freedom of action at the point of entry.

The Normandy landings on 6 June 1944 demonstrate this logic. D-Day was a contested entry, aimed at gaining a foothold on the European continent. The Allies dropped airborne divisions behind German lines to secure key bridges, disrupt communications, and limit enemy reinforcements.⁵ Amphibious forces fought their way ashore against prepared positions. What prevented failure was not a single capability but integration across the joint force. Naval gunfire and aerial bombardment shaped the battlespace before the assault.⁶ Engineers breached obstacles, cleared lanes, and enabled movement off the beaches. Specialized armored vehicles—designed to clear mines, reduce fortifications, and transport troops—worked in concert with infantry to create and exploit gaps.⁷

Despite early setbacks, the combined efforts of infantry, armor, artillery, and engineers gradually adapted to battlefield conditions. By the end of the day, the Allies had secured all five beachheads and established a lodgment in France. The landings were not a decisive victory, but they did not need to be. The break-in succeeded because it created the conditions for what followed: the buildup of combat power and the transition to operations in depth.

The modern battlefield requires a similar approach. A successful break-in requires infantry-centric combined-arms formations, properly resourced and integrated within a joint force. Engineers breach layered obstacles. Joint fires, including army artillery such as long-range precision fires, and air power suppress and dislocate critical enemy systems. Armor detachments provide protection and lethality at the point of contact. Autonomous, unmanned ground and aerial systems, combined with direct liaison to special operations forces, enable the detection of high-payoff targets, unmanned breaching, and logistical resupply—all of which are essential for expanding the lodgment. Just as Allied airpower proved decisive during the Normandy landings, executing a modern break-in demands localized air superiority to enable a joint force commander and staff to synchronize multidomain convergence, ultimately enabling the foothold achieved by infantry-centric combined-arms formations.

As units plan to implement the framework, they must consider the elements of operational art.⁸ Among the elements, tempo is critical to the execution of this framework. By linking actions in time and space, tempo sustains momentum across echelons and prevents the enemy from recovering. In the break-in, tempo is measured by how quickly a force can transition from contested entry to a secure lodgment, denying the enemy time to disrupt the buildup of combat power. Maintaining tempo allows for a continuous flow into the breakthrough.

Break Through

The breakthrough is a modern penetration—the moment when a force kicks the door in and turns access into opportunity. It is a form of maneuver executed on a narrow front, chosen when no assailable flank exists.⁹ Success depends on identifying a point of weakness, concentrating overwhelming combat power, and rupturing the defense’s continuity. But penetration alone is insufficient. To matter, it must extend deep enough—typically 25–75 km—to prevent the enemy from restoring coherence and sealing the breach. Speed and flexibility are also essential to achieve the required depth, respond to inevitable battlefield changes, and transition rapidly to respond to enemy counterattacks.

Operation Cobra highlights this transition from entry to breakthrough. In the aftermath of the grinding attrition that followed the Normandy landings, American forces faced a battlefield that bore an uncomfortable resemblance to earlier positional wars devoid of maneuver: dense hedgerows, constricted fields of fire, and a German defense optimized for delay. Operation Cobra was designed to shatter that stalemate by penetrating the German lines.

The operation commenced on 25 July 1944 with a massive and narrowly concentrated aerial bombardment near Saint-Lô, France.¹⁰ Nearly three thousand US aircraft struck a confined sector along the Saint-Lô–Périers Road, with heavy bombers saturating German positions and the Panzer Lehr Division absorbing much of the destruction. Yet the preparatory fires proved imperfect. When US infantry advanced late that morning, they encountered not a shattered vacuum but reorganized German defenders. Elements of Panzer Lehr and the 5th Parachute Division, though battered, retained sufficient cohesion to contest the advance with artillery, tanks, and well-sited strongpoints.¹¹

The breakthrough did not occur on impact; it emerged from what followed. Beneath the surface, the German defense lacked depth and continuity. Allied pressure elsewhere had fixed reserves and prevented the establishment of layered positions.¹² Recognizing this, American forces adapted. Rather than employing armor in dispersed, infantry-support roles, they concentrated it. Speed, mass, and shock replaced methodical attrition. Armored divisions widened the rupture, seized key terrain, and stretched an already thinning defense. Within days, organized resistance began to collapse. What started as a contested penetration became an expanding breach. It is worth mentioning also that air superiority remained decisive throughout Operation Cobra, enabling the success of the operation. While not as intensive in the break-in, combined-arms formations will still require periods of convergence from the joint force to set conditions for maneuver.

The transition from movement to combined-arms maneuver is the essence of the breakthrough. It requires formations that can sustain tempo, absorb friction, and exploit opportunity faster than the defender can respond. During the breakthrough, tempo determines whether a penetration becomes a rupture—forces must expand the breach faster than the enemy can reposition reserves or restore defensive coherence. Maintaining this tempo requires significant combat power and resources, as sustained pressure overwhelms the enemy’s ability to respond. In the modern context, that role belongs to armored combined-arms formations. Armored formations possess the mobility, layered protection, direct and indirect firepower, and beyond-line-of-sight command and control necessary to operate at depth and tempo. Armored forces are designed to continue the attack, turning local success into operational dislocation.

Infantry forces, meanwhile, play a critical role in the breakthrough. Specifically, these formation types hold the door open, preventing the enemy from closing it and creating a salient in which armored forces become encircled, and ultimately, destroyed. Infantry forces, with joint fires and engineer support, seize key intersections, block cross-mobility corridors, and deny enemy observation from restricted terrain. By doing so, they stabilize the penetration, protect their flanks, and preserve momentum.

When properly concentrated and aligned in time and space, armored and infantry combined-arms formations do more than penetrate—they break through with the required tempo to rupture the enemy’s defense in depth. In doing so, they transform a foothold into a rupture. But rupture alone does not produce decision; it must be exploited before the enemy can recover.

Break Out

The modern breakout is an exploitation—the moment when a force turns rupture into decision. It follows a successful penetration and drives into the enemy’s depth to disorganize, collapse, and render the defense irrelevant.¹³ If the defender is arrayed in depth, exploitation is not optional; it is decisive. Without it, penetration remains a local success. With it, the enemy’s system begins to unravel; the breakout is the decisive operation.

By late July 1944, this dynamic was on full display in Normandy. Following the penetration achieved during the opening phases of Operation Cobra, German defenses opposite the US advance fractured into scattered resistance.¹⁴ While the US military was making progress, it was not yet fully out of danger posed by the restricted terrain and remaining enemy defenses. The commitment of follow-on armored forces accelerated the collapse that ensured the breakout. As German units attempted to withdraw and reconstitute, they were met with a relentless combination of armored maneuver, massed fires, and persistent air attack. Retreating columns were struck from above, while US armored formations destroyed vehicles, shattered formations, and denied any coherent reorganization. What had begun as a contested penetration became a rout.

German attempts to stabilize the front failed for a familiar reason: they could not regain coherence faster than the Allies could exploit. Reinforcements arrived piecemeal, counterattacks lacked coordination and protection, and air superiority prevented the concentration of combat power. By the end of July, the seizure of Avranches in Normandy opened the gateway out of the bocage.¹⁵ The German army in the west did not simply lose ground—it lost the ability to fight as a system.

This is the purpose of the breakout. It is the phase that converts tactical success into strategic effect by destroying the enemy’s capacity to respond. Tempo becomes the mechanism of decision, as sustained speed, endurance, and pressure prevent the enemy from reconstituting combat power and turn disorganization into collapse. Once again, armored-centric formations are crucial. Their protected mobility generates the tempo required to pursue a disintegrating enemy. Their firepower delivers shock at decisive points. Their sustainment and communications enable continuous operations far beyond the initial breach. It is this unique combination of attributes—the power to create the breach and the endurance to exploit it—that makes armored formations the critical force for achieving decisive results in modern, large-scale combat operations.

Learning the Wrong Lessons

This framework of break in, break through, and break out is not unique to Normandy in World War II. The Korean War offers another clear illustration.¹⁶ The Inchon landings in September 1950 served as a decisive break-in, an amphibious lodgment that shattered North Korean assumptions and reintroduced maneuver to the campaign. Eighth Army forces subsequently executed a breakthrough from the Pusan Perimeter, rupturing the enemy’s forward defenses and linking with forces advancing from Inchon. This convergence enabled a rapid breakout, as UN forces drove north toward the Yalu River—transforming a desperate defensive fight into an operational offensive that threatened the collapse of the North Korean regime. Israel’s operations in the Sinai during the 1967 Six-Day War offer another clear illustration.¹⁷ Israeli forces achieved a rapid break-in through preemptive air strikes and airborne operations that disrupted Egyptian command and control and secured key entry points into the peninsula. They then executed a breakthrough by concentrating armored formations against Egyptian defensive belts, rupturing prepared positions and dislocating forces that were oriented toward static defense. This set the conditions for a rapid breakout, as Israeli armored units exploited into the Sinai’s depth, encircling formations, collapsing resistance, and driving to the Suez Canal—turning initial tactical success into decisive operational advantage.

Despite repeated historical evidence, militaries have and continue to draw narrow, tactical lessons from past wars—preparing to fight the last battle more efficiently rather than learning how to win the next one decisively. In the aftermath of World War I, the French and Germans drew sharply different conclusions from the same experience. France, shaped by the trauma of attrition, invested in the Maginot Line—seeking security through fortified defense and effectively institutionalizing positional warfare. Germany, by contrast, focused on restoring decision through maneuver, developing concepts that emphasized speed, concentration, and the integration of armor, airpower, and communications—what would become known as blitzkrieg. One approach sought to avoid the next stalemate; the other sought to overcome it.

Many current observers have fallen into the same trap, trying to replicate Ukraine’s success by swapping a Maginot Line for a hyperfocus on mass-producing drones. Drones should not be treated as a stand-alone solution, but as enablers within a larger operational framework. When properly integrated, they extend the formation’s ability to see, strike, and sustain across depth—supporting each phase of the operation rather than defining it. Counterdrone efforts are also essential for survival on the modern battlefield, reducing exposure and preserving freedom of action under persistent surveillance. But they are not a cure-all; suppressing enemy drones alone will not restore maneuver or reconnect tactical success to strategic decision. Drone-enabled defenses have proven lethal but primarily in static conditions. They excel at denial, not decision. Replicating them while on the move is difficult. Focusing solely on drone warfare alone risks reinforcing the very dynamics that produce stalemate.

The focus on drones reflects a recurring tendency in warfare to overemphasize the dominant tactical capability of the moment while neglecting the operational framework required to translate its effects into decision. Drones, like previous innovations, enhance the ability to detect and strike, but they do not resolve the fundamental challenge of linking actions across depth. Without that linkage, even the most effective tactical systems risk reinforcing stalemate rather than overcoming it. Only when break in, break through, and break out are synchronized in time, space, and force can battlefield gains translate into strategic outcomes. The pattern is clear, but the implications are often ignored.

Conclusion

The character of war may evolve, but its fundamental logic endures. As World War I demonstrated—and as the Russia-Ukraine conflict now reinforces—when tactical actions remain disconnected from strategic purpose, warfare devolves into costly stalemate. The lesson is not that technology has rendered maneuver obsolete, but that maneuver must be enabled, organized, and linked through operational art.

History makes this clear. From the joint force landings at Normandy through Operation Cobra’s penetration and the subsequent exploitation across France, success emerged not from isolated actions, but from their connection. Infantry-centric forces, properly task-organized with enablers, secured an entry. Armor and infantry combined-arms formations ruptured defenses through penetration. Follow-on armored formations exploited this rupture. These operations were not accidents of courage or materiel, but the result of coherent operational art. On today’s transparent battlefield, marked by drones, layered obstacles, and long-range precision fires, that coherence is even more essential.

The next conflict will not wait for US forces to relearn these lessons under fire. Preventing a return to a modern no-man’s-land demands more than improved equipment; it demands a renewed commitment to operational art and a tactical warfighting framework that restores mobility and tempo.¹⁸ Formations, resourced with appropriate capabilities at echelon, can deliberately integrate the break in, break through, and break out framework. By doing so, the Army can ensure that tactical battles contribute to strategic outcomes, preserving freedom of maneuver and maintaining the initiative in the wars of tomorrow. If it doesn’t, the Army may find itself with a door kicked open but no one to go through it.

---

Notes

• Epigraph. Georgii Samoilovich Isserson, The Evolution of Operational Art, trans. Bruce Menning (Combat Studies Institute Press, 2013), 37, https://www.armyupress.army.mil/Portals/7/combat-studies-institute/csi-books/OperationalArt.pdf.

1. Vladimir K. Triandafillov, The Nature of the Operations of Modern Armies (Frank Cass, 1994), xxv–xxvii.
2. Isserson, The Evolution of Operational Art, 26.
3. Dorsel Boyer and Robert K. Becker, “How Ukraine Overcame the Transparent Battlefield to Achieve Operational Surprise in Kursk,” TRADOC G-2 Newsletter Red Diamond, 19 September 2024, https://oe.t2com.army.mil/product/how-ukraine-overcame-the-transparent-battlefield-to-achieve-operational-surprise-in-kursk/.
4. Jessica Sobieski et al., “Russian Offensive Campaign Assessment, February 25, 2026,” Institute for the Study of War, 25 February 2026, https://understandingwar.org/research/russia-ukraine/russian-offensive-campaign-assessment-february-25-2026/.
5. Chester Wilmot, The Struggle for Europe (Wordsworth Editions, 1997), 243.
6. Antony Beevor, D-Day: The Battle for Normandy (Viking, 2009), 91.
7. Stephen Dowling, “The Strange Tanks That Helped Win D-Day,” 6 June 2016, https://www.bbc.com/future/article/20160603-the-strange-tanks-that-helped-win-d-day.
8. Army Techniques Publication 5¬-0.1, Army Design Methodology (US Government Publishing Office [GPO], 2015), 1-6.
9. Field Manual (FM) 3-90, Tactics (US GPO, 2023), 2-15.
10. Andrew Williams, D-Day to Berlin (Hodder Pb, 2005), 180.
11. Max Hastings, Overlord: D-Day and the Battle for Normandy (Vintage Books USA, 2006), 256; Williams, D-Day to Berlin, 183.
12. Hastings, Overlord, 256.
13. FM 3-90, Tactics, 3-3.
14. Hastings, Overlord, 258.
15. Williams, D-Day to Berlin, 185.
16. Roy E. Appleman, South to the Naktong, North to the Yalu (US Army Center of Military History, 1961), 502–6.
17. George W. Gawrych, The 1973 Arab-Israeli War: The Albatross of Decisive Victory (Combat Studies Institute Press, 1996), 53–55.
18. Thomas M. Feltey and Heath Rosendale, “Restoring Fires and Maneuver: An All-Arms Wave-Based Approach at the Tactical Edge,” Military Review Online Exclusive, 18 November 2025, https://www.armyupress.army.mil/Portals/7/military-review/Archives/English/Online-Exclusive/2025/Restoring-Fires-and-Maneuver/Restoring-Fires-and-Maneuver-UA.pdf.

Back to Top