**This War on the Rocks article accompanies a larger analysis conducted before planned troop reductions in 2014. You can find the original analysis here**
How did the Taliban seize power so quickly? While the weakness of the Afghan state was no secret, the speed of the Taliban’s victory stemmed from a little-appreciated factor: their ability to use Afghanistan’s human geography to exploit that state fragility. In particular, the country’s low population density empowers fast-moving and cohesive attackers.
The country’s overall population density is low — only about 148 people per square mile (57 people per square kilometer). By comparison, Iraq’s population density is 231 people per square mile (89 people per square kilometer). Even in the populated areas of Afghanistan, people are quite spread out, with 26 percent of the population living in urban centers compared to 71 percent in Iraq. Given Afghanistan’s dispersed population, it would have been challenging for a strong state with a cohesive, mobile, and well-trained army to stand firm and counteract the Taliban’s quick-moving offensives. The Taliban did not confront that sort of opponent, of course, and they were able to conduct lightning offensives across many fronts, which fatally stressed the limited cohesion of the Afghan National Defense and Security Forces.
That scenario was foreseeable: I produced an analysis in 2012 — as the United States began troop reductions — that considered potential outcomes if the International Security Assistance Force fully withdrew from the country. Drawing on lessons from the Taliban’s ascendance in the mid-1990s, that analysis found that the weaknesses of the Afghan security forces and the state’s illegitimacy, combined with the low force-to-space ratios generated by Afghanistan’s terrain and its population distribution, made a quick Taliban victory a reasonably likely outcome.
Following the withdrawal of Western forces during the summer of 2021, the Taliban swiftly and easily occupied vast swaths of sparsely populated territory. They then used that territory to demonstrate their relative strength by launching a set of coordinated, fast-moving offensives. After establishing their military superiority, the Taliban rarely had to use force because they could leverage their geographic reach to intimidate local leaders and convince defenders to flee or surrender peacefully. If the U.S. government had prepared for the intense pressure that a rapid and far-reaching Taliban offensive would put on the Afghan army and local leaders, it could have slowed the Taliban takeover long enough to allow for the orderly evacuation of civilians and at-risk communities.
The Taliban Did This Before
During their initial rise in the 1990s, the Taliban took advantage of Afghanistan’s low population density to conquer large swaths of territory by making deals with local leaders. They then used those areas to launch blitzkrieg-like attacks that overwhelmed the forces of the Northern Alliance, an amalgam of fighters that included units from the (fleeing) central government and Tajik, Uzbek, Hazara, and Pashtun militias. Rather than rely on traditional tools such as artillery and armor, the Taliban moved quickly in weaponized pickup trucks (“technicals”) to defeat dug-in defensive positions. Low force-to-space ratios meant that defenders — particularly those without close air support — had significant ground to cover and had to move swiftly and in a coordinated fashion to stand any chance of successfully countering Taliban threats from many directions.
Not only were many of the Taliban’s foes in the 1990s hampered by limited training and mobility. They were often less cohesive than the Taliban due to the fragmented coalition of actors composing the Northern Alliance. As I observed in the 2012 analysis, in conflicts with low force-to-space ratios and limited military capabilities, cohesion is fundamental: In such scenarios, “when forces are not cohesive, they will not move in a coordinated manner to push back breakthroughs and often will be less willing to fight in numerically challenging situations, let alone counterattack under fire.”
When the Taliban faced better-trained and cohesive groups, their progress was often slowed. For example, in March 1995, organized government forces from the Central Corps, reinforced by airlifted troops from Kabul and close air support, turned back the Taliban’s first attempt to surround and seize Herat. Similarly, organized and cohesive government forces decisively withstood assaults on Kabul in 1995. Such instances emphasized the capacity of reasonably prepared troops — especially ones who had air support — to push back the type of mobile warfare used by the Taliban. Even so, in the 1990s, the Taliban’s cohesion and the sheer scale of their offensives overwhelmed the relatively limited groups of well-prepared defenders in the Northern Alliance.
How Things Went From Bad to Worse
The events of the past weeks share many similarities with the Taliban’s initial rise to power over two decades ago and bore out key aspects of what my 2012 analysis suggested might happen. In fact, the Afghan security forces of 2021 were generally worse off than anti-Taliban forces were in the 1990s. While the density and distribution of Afghanistan’s population have not changed significantly since then, in 2021 — unlike in the 1990s — the Taliban enjoyed a presence throughout the country. That allowed them to pressure the Afghan National Defense and Security Forces in multiple locations simultaneously. As a result, the Afghan military had to try to cover large swaths of territory, move quickly to respond to the Taliban’s political and military threats, and attempt to hold its own in pitched battles and counterattacks.
The Afghan security forces were not up to these tasks. The Taliban took a host of provincial capitals and Kabul itself in a matter of days, more quickly than even the most pessimistic, publicly available estimates predicted. The Afghan military lacked the capacity and cohesion required to stand firm and defend against fast-moving offensives across many fronts simultaneously. It had long been clear that it was an anemic force which was ill-prepared to take on a major challenge in a coherent and steadfast fashion. As many have noted, since summer 2013, when Afghan forces assumed the lead responsibility for security in the country, things got worse and worse. By 2021, the Afghan military was poorly organized, lacked the ability to provision and pay its soldiers consistently, and was inadequately trained.
Afghan forces had always been heavily dependent on U.S. air support for troop movement, re-supply, and combat operations. Consequently, when American air support was curtailed sharply in the spring and early summer, the Afghan military was unable to regroup or move units around quickly. That created a major strategic challenge for Afghan forces, which was compounded by the Taliban’s rushtoward many urban centers at once. In the few cases in which the Afghan security forces did successfully slow Taliban attacks, as occurred in Lashkar Gah in May of this year, it was because they enjoyed substantial U.S. close air support.
As I predicted in my earlier analysis, after the exit of Western troops, Afghan forces retreated from outposts and checkpoints to urban areas when confronted by Taliban threats, thereby ceding control of supply lines and major highways. This allowed Taliban forces to capture large areas and slowly surroundand isolate urban centers, enabling them to pressure officials for deals. Local officials were quick to accept Taliban proposals because they had little allegiance to the central government and knew that Afghan forces were unwilling (and unable) to defend their areas from Taliban offensives. The Afghan military’s lack of preparation, combined with its massive corruption and ethnic infighting, led to very low levels of cohesion and little commitment to the state. Indeed, in the areas where Afghan security forces tried to put up some resistance, many soldiers either fled or actively cooperated with approaching Taliban forces. As a result, after the Taliban demonstrated their superior offensive movement and cohesion during the U.S. drawdown in the spring and early summer, any effective resistance quickly collapsed.
What Could the United States Have Done Differently?
The Afghan security forces, as they were configured and trained by 2021, would never have been able to turn back the Taliban. Many have aptly observed that America’s approach to building partner forces should be dramatically overhauled, but the opportunity to rebuild and repurpose the Afghan military had passed long before President Joe Biden took office.
Notwithstanding that, the realities of the military contest in Afghanistan could have been better managed during the U.S. withdrawal. A small Western contingent with air support could have held the Taliban at bay for a few more months, protecting urban centers long enough to stage an orderly evacuation. For the Biden administration, this might have had less symbolic value than ending American military involvement in Afghanistan shortly before the 20th anniversary of the 9/11 attacks, but it would have provided time for the Afghan state to come to terms with the withdrawal. Although Afghan government leaders would have watched the Taliban’s territorial reach expand quickly, they would have still had outside forces helping to protect key population centers. Critically, this alternative approach would have also given the United States, and other outside governments, more time to evacuate greater numbers of Afghan allies and activists to safety.
Leaving a limited outside force in place, without significant reinforcement, could not have prevented an inevitable Taliban takeover within a matter of months. The Taliban would still have continued their creep into much of Afghanistan’s territory, positioning them to mass forces across many fronts in order to launch a large-scale violent campaign. The combination of the Afghan state’s feebleness and the low force-to-space ratios seen in Afghanistan meant that there were few prospects for long-term stability without a notably larger foreign troop presence that could continue to pressure the Taliban throughout the country’s vast territory.
The Taliban had carefully prepared their strategy and understood the physical and human terrain of Afghanistan. The Taliban were not the first non-state fighters to take the United States by surprise — prior to summer 2014, American officials similarly misinterpreted the strategic capacity of ISIL — and they won’t be the last. The U.S. government’s analysis of non-state armed actors’ capabilities should become more holistic: Policymakers and officials should recognize that such actors often develop military and political institutions that leverage the physical and human terrain in countries where complicated civil wars are being fought.