by MAJGEN Christopher R. Smith, Australian Army, & MAJ Ben Flores, USA
Landpower Essay 23-2, April 2023

In Brief

• The war in Ukraine and the past several decades of war have revealed six major emerging features of warfare: (1) warfare is taking place among bigger and denser populations; (2) populations resist occupation even when faced with a stronger adversary; (3) there is greater restraint in the use of force; (4) there is a high cost of maintaining armed forces and waging war; (5) reconnaissance strike complexes have made movement and maneuver especially deadly; and (6) there is a pronounced advantage to the defender.
• These emerging features of warfare suggest we are entering a new age of indecisive warfare characterized by stalemate, close-quarter fighting and limited war aims—despite advancements in technology.
• Armed forces will still be useful in an age of indecisive warfare. They can be used to achieve limited war objectives against an unprepared adversary and for deterrence by denial. 

Introduction

On 24 February 2022, massive Russian formations crossed the Russia-Ukraine border along multiple axes with the intent of a rapid victory. Given the brazenness and disjointed nature of the invasion, the Russian high command surely assumed a fait accompli, much like they experienced in Crimea in 2014. Over a year later, however, the war continues—with little end in sight. 

While a decisive victory has proven elusive on the battlefield in Ukraine, the war has not prevented the world’s militaries from drawing lessons about the changing character of warfare. The intensity of the past year in Ukraine, combined with the events of smaller wars over the past several decades, has revealed six major emerging features of warfare: (1) warfare is taking place among bigger and denser populations; (2) populations resist occupation at least as vigorously as at any time in the past, even when faced with a stronger and more advanced adversary; (3) there is greater restraint in the use of force, especially in the West; (4) the costs of maintaining armed forces and waging war have become oppressive; (5) reconnaissance strike complexes—the combination of far-reaching sensors and long-range precision weapons—has made movement and maneuver especially deadly; and (6) there seems to be a pronounced advantage to the defender, particularly if the defender possesses advanced reconnaissance strike capabilities. 

The implications for each of these features combine to suggest that we are entering a new age of indecisive warfare, akin to that of the era of Frederick the Great and the Duke of Marlborough, in which only limited war objectives are possible. While limited warfare is nothing new, these emerging changes to warfare run counter to some prevailing narratives about contemporary and future warfare, including rapid single campaigns, grand fait accompli and high-tech, knock-out blows culminating in decisive victory. These changes might lead nations to reconsider the relative utility of war. 

That said, war is unlikely to be entirely without utility, despite the presence of ingredients for stalemate and indecisiveness. Modest war objectives, including limited surprise attacks that turn the tactical defense to the advantage of the aggressor, might still prove useful. The main implication for these changes might be to make war more a part of complex ongoing negotiations for relative advantage between great powers and their supporting blocs. Perhaps Russian military planners should have paid closer attention to the various wars of recent decades in order to avoid the predicament they are currently in—one resembling the conditions of 1916, albeit with the technologies and demographics of the 21st century. 
 

Bigger and Denser Populations

There is no separating warfare from the environment where people live, which is increasingly in urban spaces. In 2018, according to the United Nations, an estimated 55 percent of the world’s population—over 4 billion people—lived in urban areas; that number is projected to increase to 60 percent by 2030. Under this projection, one-third of the global population will be living in cities with at least half a million inhabitants by the end of the decade.¹ People are increasingly living in bigger and denser populations, which, in turn, has affected where wars have been fought. The cities of Kyiv, Mariupol, Kharkiv and Kherson became the epicenters of Russian assaults and Ukrainian counter-assaults last year, while scores of smaller Ukrainian cities and towns saw their own share of intense urban combat. The conditions of these battles were not much different from the earlier 21st century urban battles of Mosul, Aleppo, Fallujah and Grozny. In all of these cases, changes in demographics ran headfirst into changes in warfare.

Bigger and denser populations mean that combat, ground combat in particular, will find its ways into urban areas. Throughout history, major cities have served as key terrain for opposing armies, even if the military benefit of capturing such cities has been questionable. The challenge for the attacker today is that these cities are much larger and there are more of them. A small village that might have been easily bypassed or seized in 1950 may now consist of hundreds of thousands of people and tens of square miles of dense urban terrain. Expanding further, try to imagine what an assault on a mega-city like Dhaka, with its 22 million inhabitants, would look like. The size and complexity of these cities make them attractive to defenders, which, in turn, draws out the attention of the attacker—even if that attacker wishes to avoid a prolonged urban fight. If either side is looking for a fairer fight, urban terrain greatly mitigates the advantages of 21st century weaponry and reconnaissance platforms and belies an adversary’s optimistic timelines. Urban terrain draws in large numbers of troops, particularly for the attacker. Forced to fight block by block, stalemate and indecisiveness become all the more likely. 

More important, large and dense populations are hard to bring to heel. Even absent a major urban battle, they require enormous armies just for occupation. At the height of the Iraq War, the U.S.-led coalition dedicated an entire division out of four—Multi-National Division Baghdad—to the occupation of the Iraqi capital. The demands of occupying a city of some six million people, which included a fair share of pitched street battles, drew forces away from insurgent sanctuaries in the countryside and prevented significant reinforcement of troubled areas like the Sunni Triangle. Ultimately, the challenges associated with occupation of a city are in a direct competition for resources with the challenges that would wage battle to achieve overall war aims. Serious occupation of any major city would be a major draw on resources, increasing the overall cost of waging a war, making indecisiveness and costly stalemate all the more likely. 
 

Populations Tend to Resist Occupation

If the old Cold War adversaries, the United States and Russia, have experienced anything in common in the past 20 years, it would be active and vigorous resistance to their occupying forces. Bigger and more advanced militaries, backed by larger GDPs (gross domestic products) and populations, have not deterred popular armed resistance to foreign occupation, nor have they stopped civilians from providing the necessary support to sustain such resistance. In the case of the United States, the invasions of Afghanistan and Iraq and the corresponding initial defeats of the Taliban and Saddam Hussein’s regime were, in a sense, quite easy. The challenge came from the ensuing occupations, which dragged each war out far past what military planners had anticipated. In fact, the occupations became the wars themselves, where the high-tech American war machine faced off against lightly armed insurgents. Backed by segments of the population, the forces of resistance fought the United States to a virtual draw in Iraq and to defeat in Afghanistan. American cash, fire power, gadgets and altruism were not enough to overcome the stalemate brought about by popular armed resistance. 

Russia’s circumstances have provided a case study in what happens when popular resistance joins forces with a competent and well-equipped military. It seems that Russia developed portions of its strategy under the assumption that Ukraine’s will to resist would quickly collapse in the face of a major Russian assault, which, in turn, would prevent any opportunity for a response from the collective West and NATO. Despite the resistance they have experienced in the Donbas since 2014, Russia failed to recognize the tendency for contemporary citizenry to vigorously resist occupation and aggression. And, unlike the American experience in Iraq and Afghanistan, the Russian military is being ground down in its occupation of Ukrainian territory by a conventional force that is defending its homeland. Also, the abundant aide provided by NATO cannot be discounted; however, the use of such aide is only made possible by the Ukrainian determination to defeat Russia. 

The big lesson for smaller nations the world over is that mobilizing the popular will to resist is a sound adjunct to any strategy when facing a stronger military. Popular resistance draws resources away from an adversary, extends conflict, invites stalemate and lessens the chance of decisive victory in warfare. The prevalence of larger and denser populations combined with the sheer costs of occupation make the effectiveness of popular resistance all the more likely. 
 

Restraint in the Use of Force

Restraint in the use of force in war is not a new phenomenon; but, despite the heavy reporting of civilian casualties in recent wars, restraint by armed forces has arguably never been greater than it is today. These heightened levels of restraint are principally due to moral and ethical expectations of Western peoples, but even countries that are willing to terrorize civilian populations seem to be more restrained these days than they have been in the past. Russia’s current and seemingly deliberate targeting of civilians is actually quite restrained when compared with the historical prevalence of such tactics. 

Whereas the Russians have shown through their actions in Ukraine and Syria at least some willingness to use terror against the civilian population to achieve their objectives, the West is not as willing to utilize such tactics. While U.S. military operations during the Global War on Terror led to civilian deaths, such deaths were never the direct goal of U.S. policy. On the contrary, the mitigation of such collateral damage was a serious and comprehensive consideration for every operation—and adversaries used this to their advantage in Iraq and Afghanistan by staging and fighting from among civilian populations in both cities and villages. In these cases, the added complexity of separating combatant from non-combatant prevented decisive maneuver and led to more deliberate and methodical operations. The moral restraint of almost two decades’ worth of counter-insurgency operations in these two countries was a significant factor that contributed to the long stalemate experienced in both of them. 

The advent of precision-guided weapons has served only to accentuate restraint in warfare. The growing precision of modern weapon systems has been met by a commensurate growth in public expectations of more discerning targeting that limits the unnecessary deaths of both combatants and non-combatants alike. Gone are the days of carpet-bombing urban areas. Popular expectations for “clean” and “surgical” strikes have made the death of innocents all the more unacceptable. While these developments are without exception positive, one of their consequences is a contribution to the indecisiveness of contemporary warfare. 

The last point notwithstanding, while ethical and moral factors have limited military forces in what they can bring to bear in a conflict, these factors have had much less effect on insurgents, who seem just as willing to use terror to achieve their war objectives as at any time previous. While this exception runs counter to the general trend of greater restraint in warfare, the exception also serves to reinforce the conditions for stalemate in contemporary warfare.
 

The Cost of Maintaining Armed Forces

Waging war aside, the cost of maintaining a professional military that is capable of waging war has greatly increased. Personnel costs have gradually risen over the last several decades. The United States commits roughly one quarter of its over $800 billion defense budget to personnel costs to maintain its all-volunteer force.² While this has largely been a net positive for the standard of living for servicemembers and their families, it naturally and unavoidably affects budget decisions. Any cuts to the budget, or increased investment in modernization programs, will have to come from somewhere; cost cutting will likely come at the expense of the size of the force. The U.S. Army has already experienced this phenomenon, seeing its endstrength cut to 452,000 Soldiers in the most recent National Defense Authorization Act.³ Similarly, other professional militaries have seen their personnel endstrength decrease over the past decade. South Korea, for example, despite the ever-present threat to its north, downsized its active-duty force from 618,000 to 500,000 from 2018 to 2022.⁴ Even China’s People’s Liberation Army (PLA) cut its active force by 300,000 personnel over the last decade in order to invest more in modernization efforts.⁵ Paying military personnel is expensive, and it is becoming increasingly expensive, particularly for advanced societies. 

As technology advances, military equipment has also become more expensive, which further stresses defense budgets. There is no doubt that new technologies bring new capabilities to the battlefield—often decisive capabilities, under the right circumstances—but they come at a literal cost. A single hypersonic missile, estimated to cost as much as $10 million, comes with quite the price tag.⁶ The same amount of money could buy approximately 5,000 155mm shells.⁷ Such a comparison does not even consider production times associated with the two munition types. Examining the potential technological advantages, it becomes a matter of quality over quantity; the most common assumption is that advanced systems, platforms and exquisite munitions will win the day. 

Even so, the amount of advanced hardware on hand will be depleted in the early stages of an extended conflict, potentially increasing the likelihood of indecisive warfare. During stalemate on the battlefield, a combatant’s military industrial base, and not any particular exquisite munition, could prove to be the decisive factor—but a robust industrial base readied for the production of large quantities of modern conventional munitions and materiel is also expensive to sustain.

Arguably, the combination of expensive troops, expensive equipment and expensive sustainment costs is the cause for smaller armies. Combined with a reluctance to risk the destruction of expensive, advanced, armed forces, the great costs of maintaining modern armed forces bears some similarity to the age of limited and indecisive warfare that we saw in the 18th century. Regardless of the Ukraine War’s eventual result, Russia has a tall task ahead of it to rebuild its decimated military—it has already tapped into war stocks dating back a half century. Even if it achieves victory on the battlefield, Russia will be paying the bill far into the future, especially given the costs of occupying any territory it manages to retain. Realistically, one stalemate might lead into another. 
 

Reconnaissance Strike Complexes

Advances in sensors, drones, satellites and other surveillance platforms, combined with long-range precision weapons, have made movement, maneuver and the protection of forces (especially in open terrain, be it on land or sea) much more difficult. Upon first glance, these reconnaissance strike complexes appear to be the decisive component of warfare because anything caught in the open can be easily discovered and seemingly just as easily destroyed. U.S. dominance in the First Gulf War, its targeted killings of individuals during the Global War on Terror and, more recently, Azerbaijani success against Armenian troops caught in the open, lend support to this assertion, at least on the tactical level. On closer examination, however, the effects of reconnaissance strike complexes are not much different from the “dumb” shells and bombs that adversaries have been lobbing at each other for centuries. They shape battlefield calculus at the tactical, operational and even strategic level, but they are not the solution to waging a successful war or even to deterring an adversary. They set the parameters from which forces, particularly ground forces, have to operate. The key difference is that there is much more unsafe space than ever before.

Reconnaissance strike complexes have arguably created a new “no-man’s-land” in the modern era, stretching across hundreds or even thousands of kilometers rather than the hundreds of meters that we saw in World War I. As seen in Ukraine, Russian and Ukrainian forces operating in the open have been destroyed both by precision guided weapons and by conventional artillery supported by drone and satellite reconnaissance. The war has entered a stalemate, with trench systems popping up across the front to provide protection, resembling something straight out of 1915. Merging with these trench systems are towns and cities. Resembling images of Stalingrad, they provide similar protections against sensors and missiles. The challenge for both the Russian and Ukrainian commands is similar to the one faced by the warring powers of the Great War: how do you get across such a vast no-man’s-land and have enough forces to be decisive? Added to this challenge in the 21st century is that the once-safe logistics nodes in the rear now sit inside the new no-man’s-land and are no longer safe from attack, as evidenced by the successes of Ukrainian HIMARS (High Mobility Artillery Rocket System) strikes.

Moving to the Pacific region, in a more hypothetical scenario, the massive anti-access/area denial bubble that is spreading from the coast of mainland China provides a significant challenge for any forces wishing to cross into it. During any conflict, the PLA Rocket Force and its multi-domain sensors arrayed across the region would turn vast swaths of the Pacific into no-man’s-land for traditional surface combatants and support vessels. Perhaps “no-man’s-sea” will become a more appropriate term. Ironically, land would likely prove to be safer than the open seas under these circumstances, given the potential to exercise sea denial (or even sea control, in some instances) from the land. In a cross-strait invasion, for example, Taiwan’s best chance for survival might be to draw the PLA into dense urban terrain and underground fortresses, as a recent article from the U.S. Naval Institute argues.⁸ One can imagine an epic island-wide battle that looks like a cross between Stalingrad and Iwo Jima. Urban terrain will provide the best protection against any advanced reconnaissance strike complexes of the PLA, especially if an amphibious landing were to prove successful. Additionally, cities like those on the Taiwan coast offer a non-linear front that could vex an attacker more than any trench system ever could. To that end, the tendency to stalemate and indecisiveness in warfare would likely and markedly favor the defender. 
 

Advantage of the Defense

While the defender has tended to have a tactical advantage over the attacker for most of the history of warfare, the advantage to the defender seems to be at a peak in this age. Combat in the open is not ideal when drones and satellites can pick up movement for long-range precision strikes. The destruction of Russian targets deep behind the front in the recent war is evidence of this phenomenon. Urban terrain provides ample cover and concealment—and there is more of it than ever before in human history. It is not enough to have sensor and fire superiority when land still must be seized from a determined opponent that is using the terrain to its advantage. For example, it took the Iraqi Army nine months of close combat to retake Mosul in 2017, despite the support from a U.S.-led and largely Western coalition with unchallenged air supremacy, constant surveillance and precision munitions. The Ukrainians have similarly taken to their cities to moderate the effects of Russia’s advanced capabilities. The holdout in Mariupol is a good example. Looking at these recent battles, it is not far off to compare the deliberate and bloody seizure of cities to the Pacific island-hopping of World War II. The cities are akin to the islands that were fortified by the Japanese, and the open spaces both on land and at sea are like the oceans in between. The difference these days is that the open spaces are arguably the most dangerous places to be. 

The advantages of the defense can also serve as a spoiler for any belligerent hoping for a short war. Stalemate may very well be the strategy. By forcing an adversary into close combat, likely in urban terrain, the defenders can buy time for everything from increased aid to intervention from an outside power, preparations for a counterattack, or a more favorable political settlement. Prolonged wars also change the tactics used as war stocks are depleted, lives are lost and populations feel the strains of war. While the advantage to the defense is nothing new, its reemergence as a major feature of warfare flies in the face of discourse that triumphs offensive maneuvers and the massing of lethal and nonlethal effects for a rapid victory. Defensive war is indecisive by nature, and its increasing prevalence may lead an aggressor nation to pause in its use of overwhelming force. If the current state of the Ukraine War is any indicator, the future of warfare will be less about missile exchanges complimented by space and cyber effects (though they will play a role) and more about old-fashioned, close-quarters fighting. 
 

Conclusion: An Age of Indecisive Warfare

Despite advancements in military technology and the promise of decisiveness in war, we appear to be entering an age of indecisive warfare. Demographic and military changes over the past several decades have led to an environment that benefits defensive warfare more so than any time since at least 1917. While advancements in sensors and long-range precision fires have made it much easier to find and kill, they remain incapable of seizing, occupying and holding terrain. Spirited defenders, inspired by massive popular resistance and possessing advanced sensors and long-range systems, will inevitably use this terrain to their advantage, challenging an aggressor to fight on the ground for it. When this terrain is a city, the attacker will have to approach the city across open spaces that are constantly under threat from attack from accurate long-range fires, fighting at close quarters where the advantages of the attacker’s fires and sensors are greatly inhibited. If we look at Aleppo, Mosul or even Bakhmut, we see that fighting over such terrain takes time; this only serves to frustrate an aggressor’s hopes for a quick and decisive victory.

A protracted stalemate creates additional challenges. As we are seeing in Ukraine in real time, popular will, munitions stocks and industrial bases still matter in the conduct of warfare, just as they did one hundred years ago. The massive rate of artillery fire in Ukraine alone is forcing nations the world over to re-examine stockpiles and production capacity for a potential war. Stalemate, a term that at least the United States has avoided since the Korean War, is back in vogue. What we are seeing is more continuity than change.⁹ Despite the use of cyber warfare, drones and exquisite munitions, the war in Ukraine resembles 1917 more than it does some futuristic war out of a video game or science fiction. And so too did the fight against ISIS—and perhaps also any other war of the past 25 years.
 

Pallets of ammunition bound for Ukraine are shown in the cargo hold of a C-17 Globemaster III at Dover Air Force Base, Delaware, 9 August 2022. DoD is continuing to provide Ukraine with critical capabilities to defend against Russian aggression under the Ukraine Security Assistance Initiative (U.S. Air Force photo by Airman First Class Cydney Lee).

So, what are the implications for this indecisive warfare? For starters, armed force as a tool of foreign policy has potentially diminished. Nations might think twice about waging war if there is a high potential for a costly battlefield stalemate like we are seeing in Ukraine, or a drawn-out insurgency like the United States experienced in Iraq and Afghanistan, or both. All the high-tech weaponry in the world cannot easily solve such scenarios. That weaponry will continue to exist and provide distinct advantages to the countries that can afford it, but it will likely only fulfil the role of providing a new context for close combat rather than supplanting it.

The diminished utility of armed force as a tool of foreign policy does not mean armed force has ceased to be useful at all. Just as in the age of limited warfare of the 1700s, where European leaders like Frederick the Great used their expensive armies to achieve limited objectives for significant worthwhile ends, so too can modern armed forces achieve important results with limited war objectives. Channeling the ethos of the 1700s, a nation of today can still use its military force to rapidly seize and occupy a small piece of territory at little cost in order to use it as a bargaining chip for a larger political objective or negotiation. The victim of such an attack will have to decide whether or not to take back the territory against an aggressor using the immense advantages of modern tactical defense. It invites the victim to ponder whether a relatively small objective is worth the cost of a potential protracted war—hard to say. The United Kingdom’s counterattack to recapture the Falkland Islands after Argentina’s surprise attack in 1982 is an example of a government deciding that the objective is worth the risk. On the other hand, the Ukrainians, despite the success they have had in beating back large portions of Russia’s 2022 invasion force, have yet to regain the territory lost back in 2014. Limited objectives, seized quickly from an unprepared or poorly prepared victim, are potentially low risk and low cost when protracted war and stalemate are the alternatives.

Given the potential important advantages available to a side that is able to rapidly seize poorly defended territory, the challenge of deterring attacks by denial becomes important. To deter rapid surprise seizures, defenders will either have to be prepared to use retaliatory punishment as a threat, or must have sufficient and properly prepared forces that are disposed to defend any valuable territory that might be vulnerable to a fait accompli seizure. A military that is capable of prolonging a war, particularly on the defense, is likely to cause an aggressor to reconsider an intention to attack. But the cost of maintaining ready forces of sufficient size in forward fortified positions to deny an aggressor a limited objective (or forces ready to rapidly occupy prepared forward positions) is likely to be very high indeed.¹⁰

If there is indeed a new age of indecisive war for limited objectives, there is also a need for some new thought on strategies for dealing with it. While the functions of rapid seizure of limited territorial objectives and its counter, deterrence by denial, are joint tasks, land forces will inevitably play a decisive and essential role, even if those objectives are islands. To that end, the U.S. Army should play a leading role in the thinking and experiments necessary to adapt to the challenges of this new age of warfare, including—perhaps particularly—for contingencies in the Indo-Pacific.

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Major General Christopher R. Smith, Australian Army, is the Deputy Commanding General (Strategy and Plans), U.S. Army Pacific. He previously served as the Director General Land Operations (G3) of the Australian Army, Director General Strategic Planning, Army Director Plans–Army; Chief of Staff to the Chief of the Defence Force; and Chief of the Defence Force’s Liaison Officer to the Chairman of Joint Chiefs of Staff. He has served on operations in Afghanistan, Iraq, Lebanon, Golan Heights and Rwanda. Smith has a Master of Military Art and Science from the United States Army Command and General Staff College and a BA from the University of New South Wales. 

Major Ben Flores, USA, currently serves as the Executive Officer for the Deputy Commanding General (Strategy and Plans), U.S. Army Pacific. He has served in a variety of assignments in Stryker, Air Assault and Airborne units including Stryker Platoon Leader, Scout Platoon Leader, Company Executive Officer, Assistant Operations Officer, Weapons Company Commander, Battalion Operations Officer and Battalion Executive Officer. His operational experience includes two deployments to Iraq and one to Afghanistan. Flores has a BS in History from West Point and an MA in History from the University of Arizona.

Notes▼

The views and opinions of our authors do not necessarily reflect the views of the Association of the United States Army. An article selected for publication represents research by the author(s) which, in the opinion of the Association, will contribute to the discussion of a particular defense or national security issue. These articles should not be taken to represent the views of the Department of the Army, the Department of Defense, the United States government, the Association of the United States Army or its members.