Why Is It So Tough to Withdraw from Afghanistan?

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Twice in the past three weeks, President Joe Biden has commented publicly on how difficult it would be to withdraw all U.S. non-diplomatic personnel from Afghanistan by the deadline stipulated in the U.S.-Taliban agreement. “It’s going to be hard to meet the May 1 deadline,” he said in his first press conference, “just in terms of tactical reasons, it’s hard to get those troops out.” While the sheer duration of U.S. combat operations in Afghanistan, Iraq, Syria, and elsewhere illustrates how politically difficult it is for the White House to completely disengage from U.S. counter-terrorism efforts overseas, in this case the president’s comments were referring to how tough it would be to do so logistically. But why are the logistics so hard? What are the “tactical reasons” Biden refers to?

Large military withdrawals are complex operations — especially those that require a complete drawdown of troops and equipment in theater. The mechanics of withdrawing troops and their equipment through an insecure environment, transferring or destroying excess matériel and facilities, and then transporting everything else out of theater requires time and effort to do in an orderly way. In Afghanistan, the process is further complicated by geographic, diplomatic, and legal constraints. The United States could withdraw its forces over the next few weeks, but it would be difficult and enormously costly. It would almost certainly require pulling transportation and logistical resources away from other missions around the world, abandoning a bunch of perfectly good equipment in Afghanistan, signing expensive contracts for quick-turn transportation capacity, leaving allied and partner forces in Afghanistan twisting in the wind, and potentially increasing the risk to U.S. troops on the ground during the withdrawal. If the United States is unwilling to pay these costs — and it appears Biden is unwilling — it will likely need some number of months, not weeks, to complete a full withdrawal from Afghanistan.

Current U.S. Force Posture in Afghanistan

The United States currently has between 2,500 and 3,500 troops on the ground in Afghanistan alongside about 7,000 or so from its allies in NATO, for a total of around 10,000 troops that would need to be withdrawn. While the United States could in theory leave NATO forces to their own devices, that seems unlikely given the Biden administration’s goal of repairing the U.S.-NATO relationship and Secretary of State Tony Blinken’s recent statement that the United States and NATO would “leave together.” Adding contractors — which the U.S.-Taliban agreement states must leave Afghanistan as well — increases the total number of people for withdrawal to somewhere in the range of 15,000 to 20,000.



The vast majority of these people are housed on roughly 12 to 15 bases, which include considerable amounts of military and other equipment required to support their basic needs and daily operations. For example, on every base, there are assortments of high-mobility multipurpose wheeled vehicles, mine-resistant ambush protected vehicles, and related all-terrain vehicles that are used for combat operations, as well as smaller vehicles such as M-Gators and ruggedized golf carts used to move around the bases themselves. There are stacks of shipping containers, some of which are housing units and office spaces, and some of which are filled with supplies, equipment, and military gear. And some bases have aircraft — drones and helicopters — that cannot fly out of Afghanistan by themselves.

In terms of raw capacity, the U.S. military has the assets to pull all of these people out by May 1. For example, a single C-17 can carry 188 passengers, which means it would take 80 to 106 sorties to withdraw 15,000 to 20,000 people from Afghanistan. Even at the moderate pace of eight C-17 sorties per day, it would take only about two weeks to fly all those people out. The U.S. military has 223 C-17s in total. But of course, raw capacity does not translate directly into the “safe and orderly” withdrawal that Biden has promised if he decides to leave. That goal requires a notable amount of sophisticated planning and sequencing of logistics operations — which take time to do well — in order to draw down the U.S. and NATO presence in a safe and methodical way.

In his excellent new book on the U.S. experience in Afghanistan’s Pech Valley, The Hardest Place, author Wesley Morgan describes the tactical pullout of a few U.S. Army companies (several hundred soldiers) from roughly a half-dozen combat outposts in Afghanistan’s infamous Korengal Valley, as follows:

It was going to take twenty helicopter flights a day for four days to get everybody and everything — including half a million pounds of equipment — out of the outposts that needed to go. [U.S. Army] Rangers and a company of [Afghan National Army] Commandos were going to fly in for the evacuation too, to provide extra security.

While this is a small, tactical example, it illustrates several of the physical challenges that need to be overcome to withdraw forces from Afghanistan. For example, it shows the required scale of withdrawal efforts (and associated pre-mission planning) relative to the number of combat troops involved. It also illustrates the additional costs imposed by the requirement for continuous security of troops and equipment on the ground. These include real and opportunity costs for military assets (including the deployment of additional troops) being used to cover the withdrawal as opposed to being used for offensive operations. And it hints at the requirement for secure positions to which to move the people and equipment being withdrawn.

The Logistics of a Complete Drawdown

Of course, the United States has removed forces and equipment from Afghanistan before, most notably in 2014. While the United States undoubtedly learned some lessons from that experience that will help it in a final withdrawal, there are important differences between removing some troops and equipment from a theater of conflict and removing all troops and equipment. As suggested above, while analysts often use troop levels as a benchmark, they can usually be removed much faster and with less difficulty than their equipment. Equipment — especially, but not only, vehicles — is heavy and bulky, and usually requires significantly more time to clean and prepare for inter-theater transport than personnel. Further, legal constraints prevent U.S. forces from simply walking away from equipment and facilities they would rather not retrograde. Only certain categories of equipment can be transferred to the Afghan government, for example. And before the U.S. military can destroy a piece of equipment still in good working order, it must either certify that there was no way to reuse or transfer it, or certify that a cost comparison determined destruction was the most cost-effective option. To meet these requirements requires an enormous amount of effort and coordination across multiple layers of the military bureaucracy.

In a partial drawdown, the military can usually remove a bunch of troops quickly to hit the target troop level while leaving a disproportionate share of the equipment behind for the residual force to either demilitarize or retrograde. The preferred “hub-and-spoke” drawdown technique U.S. forces used successfully during the 2014 drawdown — in which the United States moved people and equipment from smaller bases that were being closed to larger bases that were being retained (such as Bagram and Kandahar airfields) — naturally lends itself to this approach. But when the target is zero troops (and zero contractors) by a specific deadline, the military loses the flexibility that a residual force provides, which necessarily changes the way it plans and executes the drawdown, and almost always makes the final phase “tough.”

To get out by May 1, the United States would need to remove both its troops and a large portion of their equipment quickly. While the United States has recent experience withdrawing quickly from Iraq in 2011, in that case it was able to drive and haul the last of its people and equipment over land to bases in Kuwait, where it had the luxury of secure facilities to process the last of the items being withdrawn. In the case of Afghanistan, the United States will not be able to drive the last of its people and gear into a neighboring country. As a result, redeployment from Afghanistan typically requires troops and equipment to move over different supply lines using different modes of transportation, at different rates and with different in-transit requirements. When the United States drew down its surge forces from Afghanistan in 2014, most of the troops were flown directly out of country to regional way-stops and to their home station shortly thereafter. Their gear, on the other hand, was removed using a combination of airlift over Pakistan to U.S. bases in Gulf countries, trucking through Pakistan to various ports in that country, and combinations of rail and truck shipments through the Central Asian states to various ports on the Caspian, Black, and Baltic seas. This process, naturally, was much slower, and had to be carefully choreographed to avoid leaving people or equipment exposed to hostile forces on the ground.

Because of the insecure environment in Afghanistan, the U.S. military cannot allow a situation in which there are troops on the ground without equipment, nor can it allow one in which there is equipment on the ground without troops. Therefore, to truly be safe and orderly, the drawdown may even require a temporary surge of additional troops and equipment, further slowing the speed of the withdrawal. During the 2014 drawdown from Afghanistan, the 1st Theater Sustainment Command deployed logistics brigades to each of the regional command areas to facilitate the retrograde (which proved to be an effective way to apply the logistical expertise of these units). A rapid drawdown of forces in Afghanistan would likely, at a minimum, require a surge in aviation maintenance and ground support personnel to handle the influx of aircraft sorties that would be necessary to make the deadline. These forces, of course, need to be protected as they move and operate in the country, which increases both the security and sustainment requirements on the ground.

Several aspects of the current situation in Afghanistan conspire to make a withdrawal even more complicated. The level of violence means that units should retain enough capability to protect themselves and their equipment most of the way through the retrograde process, which imposes constraints on what can be packed and when, and what can be separated from the unit and when. While the “secret annexes” of the U.S.-Taliban agreement reportedly stipulate that the Taliban will not attack U.S. and NATO forces, neither the United States nor NATO would likely trust local Taliban units to completely adhere to that agreement as the withdrawal occurs, and the threat of attacks from Islamic State and other terrorist groups would remain. The fact that the U.S. military provides logistical and other support to its allies and partner forces in the country likewise means that the pace and order of the withdrawal should account for the distinct requirements of these forces as well. This includes NATO forces, which likely will expect some help from the United States as they withdraw. It also includes Afghan forces, who will likely be expected to take control of the bases and any residual equipment that the United States and its NATO partners leave behind, and who will have to adjust their posture and operations to account for the departure of critical enabling capabilities such as advisers, air and fire support, and contracted maintainers and logisticians. Failure to account for the needs of these partner forces could lead to their collapse, which would increase the security risk to U.S. personnel still in the country and have significant diplomatic and reputational costs. And of course, the remote, landlocked geography and underdeveloped infrastructure of Afghanistan make it hard to move large amounts of equipment and personnel quickly — except at enormous expense and with the cooperation of Afghanistan’s neighboring states (none of which, it turns out, are likely to be as accommodating as Kuwait was during the U.S. withdrawal from Iraq in 2011).

The complexity of large-scale drawdowns means that speed is expensive, in dollar costs, opportunity costs, and reputational costs. Compressed timelines for withdrawal also increase the cost of the contracts the U.S. military relies on for part of its logistical operations, since it places increased demands on contracting companies’ assets. Compressed timelines also mean that U.S. Transportation Command needs to dedicate a larger portion of its available assets to the drawdown (i.e., to conduct as many aircraft sorties as possible in a short time). The change to its posture increases the risk to other U.S. interests around the world by reducing the command’s ability to support other military operations. A quick withdrawal would also mean that otherwise minor delays and hiccups that could be absorbed in the course of a normal withdrawal process may instead result in the need to destroy or demilitarize equipment that would have otherwise been cost-effective to bring home. For example, even with the advantage of a residual force, the U.S. military still destroyed over $7 billion worth of military equipment in Afghanistan during the surge drawdown in 2014. Withdrawing in a matter of weeks would also give the United States less time to coordinate with its allies and partners to ensure that withdrawing does not leave them in an untenable or unnecessarily dangerous position, as Sameer Lalwani noted in a recent War on the Rocks article.

When would the United States cross the threshold for no longer being able to conduct an organized withdrawal by May 1? Given the complexities described above, there is no clean break on the calendar between “safe and orderly” and “unsafe and disorderly.” Rather, large-scale drawdowns tend to get more difficult, more chaotic, and more expensive as the time available to complete them decreases. As a result, the amount of time necessary to withdraw the remaining troops and equipment from Afghanistan ultimately depends on how much the United States is willing to pay to get them out — in terms of dollars, opportunity costs, reputational costs, and geopolitical risk.


The U.S. military has the raw capacity to withdraw all remaining personnel from Afghanistan in just a couple of weeks. It is less clear that it can do so without abandoning a lot of expensive equipment, leaving its NATO allies to fend for themselves, pulling U.S. Transportation Command assets away from missions elsewhere in the world, and perhaps even exposing U.S. troops on the ground to significant risk by deprioritizing tactical considerations during the withdrawal. These are real costs and risks that are a large part of what makes getting out of Afghanistan on a short timeline — whether it be May 1 or a few months down the road — so hard. The “tactical reasons” Biden cited during his press conference are thus not ones of logistical capacity, strictly speaking. Rather, they are questions of how much he is willing to pay, and risk, to overcome the logistical difficulties and associated costs of a safe and orderly withdrawal. Given the president’s comments to date, it seems he prefers a timeline of several months to withdraw from Afghanistan, not several weeks.



Ryan Baker, Ph.D., is a non-resident fellow at the Brute Krulak Center for Innovation and Creativity at Marine Corps University, and wrote his dissertation on the relationship between logistics and military power. He is also a reserve officer in the U.S. Marine Corps with active-duty experience in supply and logistics, including time overseas. The views expressed here are his, and do not necessarily represent those of the Marine Corps, Marine Corps University, the Department of Defense, or any other institution. You can find him on Twitter at @ryanbaker51.

Jonathan Schroden, Ph.D., directs the Countering Threats and Challenges Program at the CNA Corporation, a nonprofit, nonpartisan research and analysis organization based in Arlington, Virginia. His work at CNA has focused on counter-terrorism and counter-insurgency activities across much of the Middle East and South Asia, including numerous deployments to Iraq and Afghanistan. The views expressed here are his and do not necessarily represent those of CNA, the Department of the Navy, or the Department of Defense. You can find him on Twitter at @jjschroden.

Image: U.S. Marine Corps (Photo by Cpl. Dustin D. March)