‘Cunctator’ Part 2: Siege warfare and the logistics of resistance – lessons from Croatia and Iraq

By Erik A. Claessen.

This post continues from ‘Cunctator’ – Logistics, hostile environments and war in cities.

In 2006 – three years into Operation Iraqi Freedom – the US Army recognised:

“People support the source that meets their needs.”[1]

This was a confirmation that people would not intuitively support a military force which liberated them from a brutal dictator. People do seem to be willing to give their support to rag tag armed movements that use cities as bases for a resistance campaign; cities which form the hub of sustaining life as well as military action in defence of territory. These patterns of life must be understood, as well as the logistics of sustaining resistance activities, if militaries are going to be successful in campaigns where cities are central to control over the operational area. Operation Iraqi Freedom was never designed to be a long war. The American operational design at the time was commonly summarized in three words: shock and awe. The shock of a swift military regime change would inspire the awestruck Iraqi population to start a democratization process allowing the speedy redeployment of US forces. The operational design did not lead to the intended result. Instead, coalition forces got entangled in an endless series of urban battles.

Within a year after Saddam Hussein’s statue in the centre of Baghdad was torn down, the Coalition got the answer to the question why a modern military force would bother to fight in urbanized areas in the first place: because it has become impossible to govern a territory without controlling the major cities that dominate, administratively, the pattern of civilian life. After several unsuccessful attempts to pacify unruly Fallujah, coalition forces besieged it in Operation Al Fajr that took place between 7 November and 23 December 2004. In this, the 21st century resembles the 17th. In four centuries, the military pendulum concerning the decisive type of military land operations swung from sieges to battles only to return back to sieges. It would seem that Iraqi resistance movements – both Shia and Sunni – identified this reality sooner than coalition forces did, and acted accordingly.

That is not to say that nothing really changed in four centuries. Far from it. 17th century cities relied on fortifications for their defence. Once the perimeter was breached, resistance was futile. By contrast, 21st century cities can swallow up combat power and digest it. Fallujah was a good example of this contrast. After an earlier operation in Fallujah, Vigilant Resolve, US forces created a fully equipped Fallujah Brigade of Sunni soldiers to control the city. After a couple of months, the brigade’s soldiers – and their weapons – simply dissolved into the city’s population and insurgents.[2]

To develop this thesis further, and to derive the logistical implications from it, I will start with a concise overview of the conceptual approaches to siege warfare.

In 1589, Maurits of Nassau explained his strategy to defeat the Spanish forces in an address to the Dutch States-General: “I will lay siege to all cities dominating navigable rivers such as Deventer and Zutphen on the Ijssel, Nijmegen on de Waal, Grave, Venlo or Maastricht on the Maas, or Groningen. First the one, then the other. As soon as the river cities are conquered, all in-land places will fall because, cut off from their roots, they will perish by themselves.”[3]

Nassau developed a military logistical proto-system that disappeared in the fog of history after it served its purpose. The system used rivers (even the most insignificant ones) as main supply roads and small boats as trucks. Boats proved useful to transport both heavy items (like artillery pieces and ammunition) and bulky cargo (like fodder). Because these boats could not cross watershed lines, his areas of operations were limited to the river basins he could open up by besieging cities at key confluences. His failure to take Antwerp denied the Schelde basin to his forces. As a result, the border between Belgium and the Netherlands lays approximately one day’s march of the southernmost points Nassau’s supply​boats could reach in the Maas river basin without running aground. Nassau’s system allowed his forces to use cavalry and horse-drawn artillery in less fertile rural areas where fodder was scarce or during winter, when fodder was scarce everywhere.

Nassau’s mastery of river-based operational logistics defined his strategic superiority over his much more powerful Spanish opponent. However, it simultaneously limited the geographical reach that this strategy could provide. “Of all the commanders of the age, none showed himself more adept at exploiting the advantages​ offered by water-courses than Maurice of Nassau – and, conversely, no one found it more difficult to operate without them. By rapidly shipping his artillery train from east to west and back along the great rivers … Maurice succeeded in surprising the Spaniards time and again … always catching the Spanish fortresses before they could be made ready for defence. Once he got away from the rivers, however, he was lost.”[4]

A logistical system only provides a strategic advantage if it allows a belligerent to do something that his opponent cannot. It is therefore important to analyse how modern urban based belligerents tackle their logistical issues. One example is the Croatian “War of the Barracks” of 1991-1992.[5] This little known war redefined the staying power – or rather the lack thereof – of garrisoned troops. However, a CIA study regarded this conflict “one of the decisive actions of the Croatian war.”[6]

In reaction to growing nationalist unrest in Croatia, the federal Yugoslav National Army (JNA) confiscated most weapons of the regional Territorial Forces (later renamed Croatian National Guard or ZNG) in 1990. So when Croatia declared its independence in October 1991, it was militarily weak. In fact, JNA plans to nib the independence in the bud were pretty straightforward: their orders were to take the cities of Osijek and Zupaja in the north east and to conduct a two pronged attack along the Drava and Sava rivers towards the capital Zagreb. Because the terrain west of Osijek favoured a mechanized attack, the Serbs thought they could reach Zagreb in two days. The strategic objective of the lightning attack was to cause the Croatian government to collapse. Things turned out differently.

The Croatian nationalists were among the first to understand that the geographical dispersion of a nation outside its homeland can contribute to the solution of the logistical problems associated with a war of secession. In 1987, Franjo Tudjman – the political leader of the nationalists and later the first president of independent Croatia – started a systematic campaign of visits and speeches to unite the Croatian diaspora (Iseljena Hrvatska) and the Croatian homeland (Domovinska Hrvatska) in an effort to gain and secure independence. The importance of this diaspora is probably best illustrated by the fact that a Canadian of Croatian descent – Gojko Šušak – held the office of Minister of Defense during the war of secession. The funds he raised among Croatian expats covered a quarter of military expenditure in the first two years of the conflict.

More crucially, these funds allowed the secret acquisition in 1990 of the small arms needed to win the battles of the barracks. The Croatian government distributed the arms to bolster the defense of Osijek (to the north of Brcko on the map below), the fourth largest city of Croatia where the government enjoyed popular support. Furthermore, the government distributed the remaining small arms ZNG units that acted under control of municipal crisis staffs and ordered them to lay siege to all JNA barracks throughout Croatia and if possible, capture and plunder them.

By switching of their utilities, inhibiting all food shipments and – in some cases – outright armed assaults the ZNG managed to capture many barracks and gather around two hundred thousand small arms and seven hundred tanks, armoured vehicles and artillery pieces. These actions had a double effect: they stopped the Serb attack in Osijek and they blunted the JNA’s focus. Instead of concentrating on the strategic objective (the capital), the JNA diluted its fighting power in a series of efforts to relief the blockaded barracks.

However, the strategy did have its limits. To paraphrase Van Creveld, of all the commanders in the Balkan wars of the nineties, none showed himself more adept at exploiting the advantages ​offered by diasporas and popular support than Franjo Tudjman – and, conversely, no one found it more difficult to operate without them. As a result, the shape of the territory that came under Serb control seemed to defy all military logic.


Map (2)

The map was produced by the Faculty of Geography, Belgrade University, 1993 with respect to a population census taken on March 31, 1981.  The area denoted in red reflects the Serbian control of territory and has been included by the author.


This shape only makes sense by combining it with the results 1981 Yugoslav population census: the Croatian government managed to keep the territories where they enjoyed popular support, but they were unable to cut the supply lines between Serbia and the western territories they conquered, even though at its narrowest point – the Corridor of Brcko – the lines ran over a piece of terrain just three kilometres wide.

Although he firmly demonstrated the utility of a supply line of funds provided by a diaspora and the ability of cities to swallow up military power and digest it, Tudjman ultimately had to build a conventional army to recuperate the territories lost in 1991 in a series of operations executed in 1995. However, logistics-oriented strategy adopted early in the campaign was instrumental in setting the preconditions for later successes.

The Second battle for Fallujah, Operation Al-Fajr, fought by a combined US, UK and Iraqi force in 2004, also offers insights with respect to the logistics of modern siege warfare. This operation began with an intent to avoid the loss of civilian life, and a desire for combat forces to avoid being ‘consumed’ in a long-term city siege. With a whisper campaign during the summer and autumn of 2004, coalition forces convinced the overwhelming majority of the citizens to leave the city prior to the start of combat operations. After that, they methodically searched and cleared the city. However, they did not adapt their rules of engagement to the conceptual imperatives of urban administration. This meant the ‘cure’ was arguably more painful than the symptoms of the disease.

“Before the city could be returned to its residents, it needed to be cleared of unexploded ordnance, standing water, and the dead. Fallujah sits below the water level of the Euphrates River and one of the water pump stations was damaged during the battle. The standing water hid unexploded ordnance and decaying bodies. Additionally, the electric grid, water treatment, and sewage systems were in such disrepair that they needed to be replaced entirely.”[7]

The wording of the after-action review is also revealing:

“Damage to the pump station elicited a number of questions about the care taken when targeting critical infrastructure. Some have questioned, in general, the level of collateral damage within the city and asked if it was necessary. Damage to buildings was justified to save Coalition and ISF lives—they were ordered to clear the area against an enemy that came to die, that had embedded itself in such a way as to increase the likelihood of inflicting Coalition and ISF casualties.”[8]

In other words, US forces categorized pump stations, the electric grid and water treatment as “buildings”, not as vital urban infrastructure like “cloaca” or “aquaduct” as I described in part one. The loss of essential services during the siege resulted in a re-emergence of civil discord. After the siege of the Fallujah, resistance intensified in the cities around it and by 2006, Al-Anbar province that contained Fallujah was in total insurgent control. Al-Fajr was one of the operations that triggered the effort to completely rethink military ‘siege’ operations in the age of urbanization. US doctrine was adapted and the ‘Essential Services Category’ was emphasised as depicted below.


Essential Services Categories

From US Army’s 2006 edition of FM 3-24, Counterinsurgency accessible here.


The doctrinal shift underscores that conceptual approaches to the problem of contention level management at high population density revolve around a balancing act between fostering prosperity and guaranteeing security in the major cities of a conflict area. In this balance, militarily weak actors can use diaspora fundraising and municipal power structures to withstand much stronger opponents. Conversely, militarily strong actors can completely discredit themselves by demonstrating ineptitude to provide urban administration under fire.

In wars where the preservation of the urban environment is essential for the maintenance of popular support, the provision of urban services by land force logistic elements might prove as fundamental to success as the combat operations themselves. This is because city dwellers support the source that meets their needs.  This challenge will become even more significant as cities grow larger, and potential conflict zones become increasingly urbanized. Megacities are large areas with a high population density where life will depend on administrative effectiveness and the management of vital infrastructure. To cope with this reality, land forces need to adjust their understanding of initiative. and focus upon meeting the needs of the population. From a logistical point of view this calls for capabilities that not merely support military operations but that also enable the provision of urban essential services during and in the aftermath of those operations.

Colonel Erik A. Claessen is a Belgian Army logistics officer who publishes regularly on contemporary armed conflicts. Claessen is a graduate of the U.S. Army Command and General Staff College, where he earned a master of military arts and sciences degree. He writes here in a personal capacity and can be found at https://www.linkedin.com/in/erik-claessen-87341530/

[1] FM 3-24, Counterinsurgency (Washington, DC: Government Printing Office, 15 December 2006), 3-11.

[2] The analysis of the battles of Fallujah draws on the study by Dr. William Knarr and Major Robert Castro, US Marine Corps with Ms. Dianne Fuller The Battle for Fallujah, Al Fajr—the Myth-buster (Alexandria VA, Institute for Defense Analyses, 2010)

[3] Ronald P. de Graaf, Oorlog, mijn arme schapen. Een andere kijk op de Tachtigjarige Oorlog 1565-1648 (Franeker: Van Wijnen, 2004), translated by Erik A. Claessen

[4] Martin van Creveld, Supplying War: Logistics from Wallenstein to Patton, (Cambridge University Press, 2004), 2nd edition, p. 10

[5] The analysis of the “War of the barracks” draws on the study by Central Intelligence Agency, Office of Russian and European Analysis, Balkan Battlegrounds: A Military History of the Yugoslav Conflict, 1900-1995, 2 vols., (Washington, DC: Central Intelligence Agency, May 2002)

[6] Balkan Battlegrounds, Vol. 1, p. 95.

[7] Dr. William Knarr and Major Robert Castro, US Marine Corps with Ms. Dianne Fuller The Battle for Fallujah, Al Fajr—the Myth-buster (Alexandria VA, Institute for Defense Analyses, 2010), p.71

[8] Ibid., p.70


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