Urban Warfare in the Twenty-First Century. Anthony King

been vindicated. Commentators from across the spectrum have been all but unanimous about the prime cause of the rise of urban warfare in the twenty-first century:⁹ ‘The rise of urbanization – and all of the complexity it entails – increases the likelihood that at least some future conflicts will take place in cities.’¹⁰ Similarly, the US Army’s publication, Megacities and the United States Army, noted that the rise in the number of huge urban conurbations has increased the likelihood of fighting in cities. Since more people live in cities today than in the past, in often desperate conditions, it is inevitable, on this account, that conflict has and will become more metropolitan. Urbanization, in and of itself, has forced war into cities:

      The nexus between globalization, urbanization and rapid demographic growth in the ‘global South’ of the developing world appears to be changing the character of warfare. We appear to be on the cusp of an ‘urban century’ dominated by burgeoning megacities with a growing potential for violent implosions capable of causing major political crises.¹¹

      Demographics are plainly important. However, in addition to urbanization, scholars have also emphasized the asymmetric advantages of fighting in cities for weaker, nonstate insurgents. Cities offset the advanced weaponry that states possess, while maximizing the utility of suicide attacks and IEDs. Plainly, cities have always offered major defensive advantages. However, scholars have claimed that, against technologically superior state forces, contemporary cities – especially ones with rapidly growing slums – now offer the best opportunities for evasion, concealment, ambush and counterattack.¹² By operating in cities, insurgent groups also enhance the protection afforded by the laws of armed conflict and international humanitarian law. Knowing that Western powers, in particular, will seek to minimize civilian casualties, insurgents have actively sought to operate among the people.¹³ Indeed, the city offers such advantages that some have claimed that urban insurgency has constituted the major military challenge of the early twenty-first century.¹⁴

Interstate War

      When scholars invoke demographics and asymmetry, they have been mainly concerned with explaining urban insurgencies and civil conflict.¹⁵ This is not unreasonable; most urban battles this century have occurred as part of civil conflicts. Nevertheless, these scholars have also assumed that their explanations of those civil conflicts apply equally well to interstate wars. For instance, at the beginning of his work on the history of the US Army’s urban battles, Alec Wahlman argues that demography and asymmetry have been the decisive variables in determining contemporary urban warfare.¹⁶ He then goes on to analyse the battles of Aachen, Manila, Seoul and Hué. In each case, including Hué, these were battles between state forces – not between insurgents. The implication is clear. Given urban demography and asymmetry, the US Army should expect to operate in cities against peer opponents in the future, just as much as against insurgents. The same reasoning is evident in the work of Alice Hills and David Kilcullen.¹⁷ States will also fight against each other in cities because of urban demographics and the protection that cities offer against even the most advanced weaponry.

      Clearly, although interstate and civil wars have merged in the last decade into a form of hybrid conflict, some clarification is required here. Both interstate urban warfare and civil urban conflict require explanation. Yet, for the sake of clarity, it is necessary to discuss them separately. It is convenient to discuss the question of interstate warfare first and to consider why it has tended, and is increasingly likely, to converge on cities. Because scholars have focused primarily on insurgencies, they have prioritized demography and weaponry to the exclusion of all other factors. They presume that because cities have become so large, they are almost unavoidable in any future campaign. In addition, the development of advanced surveillance technologies and precision munitions will encourage even heavy state forces to take refuge within urban areas. There is no denying the importance of urban demographics and weaponry to urban warfare. They have always played a constitutive role in this kind of warfare and are likely to do so in the future. However, there is an obvious gap in the current literature.

Historically, urban warfare has also been constituted by a third factor: the size of military forces themselves. Yet, in the contemporary literature, there is almost no discussion of the size of military forces today. This factor has fleetingly been acknowledged, but never systematically investigated.¹⁸ Perhaps, because force size seems such a banal fact, its potential significance to the urbanization of interstate war has been ignored. However, by highlighting the importance of force size – numbers – it may be possible to improve on existing explanations of interstate urban warfare.

Force Size

      Force size has, of course, long been recognized as an important determinant of warfare in any era. Many military scholars have been fully aware of the significance of numbers. Hans Delbrück, the German historian, is highly pertinent here. At the beginning of his celebrated work on politics and military history, he asserted that the best starting point for the analysis of warfare was always the size of military forces. ‘Wherever the sources permit, a military-historical study does best to start with the army strengths . . . Without a definite concept of the size of the armies, therefore, a critical treatment of the historical accounts, as of the events themselves, is impossible.’¹⁹ Delbrück’s fourvolume work on military history is not a quantitative study of armies; it is a critical study of military operations, their political purposes and effects. Yet, throughout the study, he uses numbers to illustrate the special problems of campaigning and to demolish specious claims in the historiography.

      For example, in the first volume, he comprehensively destroyed the notion that Xerxes could have led a 2-million-man army when he tried to invade Greece in 480 BCE; the march column would have been 420 miles long.²⁰ The army would still have been leaving Susa when its head arrived in Greece. Delbrück also concluded, against Herodotus, that the Persian Army at Marathon in 490 BCE must have been smaller than the Greek force of 12,000, given the quality of Persian troops and the size of the actual battlefield (in the Brana Valley, not its attributed location).²¹ For Delbrück, numbers became a critical tool for interrogating military history. He was able to deduce the character of military operations merely on the basis of the size of the armies involved. Indeed, mere size had serious political repercussions.

Delbrück’s analysis is highly perceptive. However, he did not specifically discuss the relationship between force numbers and urban warfare. In order to appreciate the almost direct historical correlation between force size and urban combat, it is necessary to turn to the work of other military historians. Christopher Duffy is immediately relevant here. In his seminal analysis of the early modern fortress, he explicitly highlighted the relationship between force size and urban warfare. Duffy has shown how the trace italienne (bastion fort) was developed in response to the rise of artillery and how these forts, in turn, changed the character of both states and armies at that time. From 1500 to the mid-eighteenth century, the fortress and the siege played a critical role in military operations. Indeed, it might even be claimed that the siege – not the battle – was the defining characteristic of warfare at this time. However, Duffy notes that there was a decline in siege warfare in the course of the eighteenth century.

      Crucially, this decline had little to with improvements in armaments. Although new methods of forging artillery were discovered, which facilitated the production of lighter field guns, ballistic capabilities were not radically changed, especially in the case of siege guns. Early modern fortifications were, consequently, preserved until the 1850s. The decisive factor in the decline of siege warfare in the late eighteenth century was organizational. From the middle of the eighteenth century and especially during the era of the revolutionary wars, armies grew prodigiously. Napoleon’s Grande Armée of 1812 consisted of 1 million men; but his enemies also began to expand their forces in response. The implications for early modern fortification were profound: ‘Fortresses were also predominant because, according to a rough rule of thumb, we find the smaller the forces engaged on a theatre of war, the more importance attaches to the available strongpoints.’²² As armies grew in size at the end of the Age of Enlightenment, they were able to bypass fortresses or fortified