US Army War College

Twenty Years after 9/11: The US Army at a Crossroads

September 9, 2021   |  Colonel George Shatzer


No retrospective on the September 11 attacks can escape the bleak pall cast by the tragic events unfolding in Afghanistan today. Despite the enormous financial investment in the country and the grim human costs borne by the United States, its allies, and Afghans over the past 20 years, the US and NATO military missions have ended in ragged, ignominious failure. The question of how well these operations protected the United States and the world from Islamist terrorism remain open. But there is no doubt that the other stated purpose of creating a functioning, friendly, Afghan government and effective security forces that can prevent the reemergence of terrorism from within the country is now forfeit. 

The suicide terrorist attack on Hamid Karzai International Airport in Kabul on August 26, 2021, perpetrated by the Islamic State of Iraq and Syria – Khorasan Province that claimed the lives of 13 US servicemembers and at least 150 Afghans was a humiliating and searing punctuation to the failed campaigns.1 The irony of these operations’ names—Enduring Freedom, Freedom’s Sentinel, and Resolute Support—is now especially bitter.

The problems with the military efforts in Afghanistan began in the earliest days of the US invasion. Confusing command structures and an unclear picture of the enemy led to a lack of sufficient forces to pursue and capture Taliban and al-Qaeda fighters.2 This major US misstep permitted both groups to retain combat power they would employ in the coming months and years. At the time, senior US leaders were keen to avoid the trap the Soviets had fallen into in Afghanistan in their failed war to prop up a communist government in the 1980s—a trap the United States helped devise. Despite pouring in massive amounts of military aid and their own forces into Afghanistan, the Soviets could never break the mujahideen resistance fighters’ will and ultimately retreated to Russia, soundly defeated. Policy makers were also keen to avoid a perception by the Afghans of the United States as an occupying force. Further, the United States wanted to retain the flexibility to conduct counterterrorism operations globally, not just in Afghanistan, and ongoing commitments in places such as Korea, the Balkans, and numerous other locations constrained force availability.

The approach of first avoiding failure by not committing decisively to the military mission in Afghanistan would undercut US efforts there for the next 20 years. If nothing else, this approach created organizational and psychological effects in US and NATO units that greatly hampered mission performance.3 As just one example, six- to 12-month rotations were the norm for both deployed units and individuals throughout nearly all of the two decades of the campaign in Afghanistan. This factor alone meant US and NATO forces were perpetually a pickup team—always learning the ropes and always having one eye on the door. The short-timer mindset was so pervasive that, the commander of NATO’s Resolute Support Mission, during my tour in Afghanistan in 2014–15, admonished his staff numerous times to “[m]ake the days count, don’t count the days.”

Arguably, the United States compounded the problem of an underresourced and diluted military commitment early on by beginning, in early 2002, to prepare for the invasion of Iraq. Historians, political scientists, and military strategists will long debate the effect the planning and execution of Operation Iraqi Freedom over the next several years had on operations in Afghanistan. However, it is certain that time, focus, and forces dedicated to Iraq could have been used in Afghanistan. Whether these resources would have been used in Afghanistan or whether they would have substantially changed the outcome there will never be known.

Despite some early miscues in the military campaign, the United States initially enjoyed rapid battlefield success, but failed to consolidate these wins by struggling to prepare the new Afghan security forces for the inevitability of renewed fighting. The beginnings of a US training and advisory command would not start taking root until a year later, in the fall of 2002.4 The eventual approach to training the Afghan National Army (ANA), unfortunately, was a case study in mirror imaging. (To narrow its scope, this essay focuses on the ANA, but nearly every issue mentioned here was also present in the Afghan National Police and throughout all other elements of the Afghan National Defense and Security Forces.) The United States decided to mold the nascent ANA into a Western-style force, despite Afghan government and society being ill disposed to adopting this model. The United States and NATO typically chose to provide modern equipment Afghans could not use or maintain and to create a national army that deployed interregionally (vice a locally based, federated model of forces that would have been far more acceptable to Afghan soldiers and citizens). Frustratingly, the United States and NATO never deviated substantially from this approach during the entirety of the mission. (Various initiatives to institute locally based army, militia, and police forces were tried without success throughout the years. One of the most recent was the Afghan National Army – Territorial Force stood up in 2018. But, as the DoD reported in July 2020, the Afghan National Army – Territorial Force had “largely struggled to gain full integration and acceptance from the ANA.”5

These shortcomings alone would have severely damaged prospects for success in Afghanistan. But the failure to address Pakistan’s provision of a safe haven and support to the Taliban doomed these prospects. A basic tenet of military strategy, understood by any military professional and witnessed throughout history, holds that it is nearly impossible to defeat an enemy that enjoys sanctuary from attack and where it can rest and refit for future operations. The Taliban held this critical advantage, courtesy of Pakistan, for all 20 years of the US and NATO missions. The dynamics of the US-Pakistani relationship are complex, and the US levers to influence Pakistan are undoubtedly limited. But the United States’ decision to conduct a military campaign almost blithely while the Taliban recovered at will in Pakistan meant the United States effectively agreed to mortgage any gains it might make on the ground. Even the ANA seemed resigned to the situation, acquiescing to the Taliban’s notion of a “fighting season” and permitting it to dictate the tempo of the conflict year after year.

The net result of all these problems and challenges for the ANA was, even in 2021, it lacked nearly all the fundamental elements of a professional military force.6 The ANA was beset by endemic corruption (reflecting the state of the Afghan government) and poor leadership at all echelons. The ANA languished from bad personnel policies and systems that made filling the ranks nearly impossible and saddled the army with a massive attrition rate.7 (The attrition figure for the ANA has for years been reported by the Afghan Ministry of Defense as being between 2 and 3 percent per month, meaning essentially anywhere from a quarter to a third of ANA soldiers left its ranks every year [for all reasons, including battle injuries, desertions, and low reenlistment rates]. The Special Inspector General for Afghanistan Reconstruction, the former US organization responsible for the oversight of US efforts to oversee the development of the ANA [Combined Security Transition Command – Afghanistan], could not verify these numbers and relied on the Ministry of Defense’s reports of ANA troop strength. Thus, the true attrition rate was anyone’s guess.)8 As a result, the ANA perpetually remained a green, fledgling army. The ANA lacked any real ability to sustain its own units or maintain the equipment provided to it. The literacy rate among ANA recruits was 5 percent; thus, the literacy rate among ANA soldiers was probably about the same.9 Because the ANA never built any substantial air support of its own, it was a fixed force defending static, tactical infrastructure with little ability to move and maneuver significant distances. Surprisingly, the ANA also lacked intelligence capabilities; thus, the army could not easily plan operations (assuming it could have even conducted them) and was easily infiltrated. The insider threat of insurgents posing as ANA soldiers and then attacking US servicemembers was so concerning, US and NATO units implemented a “Guardian Angel” policy.10 Soldiers were dedicated to bodyguard duty for other US and NATO personnel working with the ANA, even at small unit levels. If senior US commanders so distrusted Afghan soldiers to stand among their personnel, how could the ANA be trusted to stand up to the Taliban? These deep-seated issues in the ANA were debilitating to it (to say nothing of the intense, ethnosectarian divides between the various Afghan peoples and the drug production and addiction problem throughout the country). As the Strategic Study Institute’s Dr. Chris Mason wrote in 2015, the ANA was clearly destined to collapse without intensive US and
NATO support.11

So, 20 years after 9/11 and its entry into Afghanistan, the US Army is at a crossroads. The Army must recognize the damage done to its credibility abroad through its failure to build viable security in Iraq and Afghanistan. In addition, the Army must restore some lost credibility at home in the aftermath of its struggle to adapt to changing societal norms and care for those in its ranks. And the Army must do all of this and much more while trying to prepare for a dangerous future defined by the accelerating growth of numerous enemies. President Joe Biden recently said the Taliban is facing an existential crisis.12 The same could be said for the Army. Today, and for the next many years, major issues confront the nation’s oldest armed service.

Doubts over US will. The Army is often the most visible expression of US will, given its presence on the ground and among the peoples in conflict zones. The departure from Afghanistan will no doubt encourage our enemies and dismay our allies and partners. Justified or not, the echoes of Vietnam and Somalia are clear. Conceding Afghanistan to the Taliban revives the old notion the United States lacks staying power and cannot stomach a tough fight. This same assessment of US mettle has encouraged terrorist groups in the past, and it will do so again. The Army must expect more terrorist attacks directed at it both at home and abroad. The Army must also expect partners will be less open to working with it and more open to cooperation with its adversaries—especially China and Russia.

Tarnished Army reputation and credibility. The disappearance of the ANA in the face of Taliban offensives in 2021 and the surrender of Iraqi security forces in 2014 to Islamic State fighters were shocking in their speed and scale. These collapses create doubt in the Army’s ability to reason through complex security challenges, combat insurgent and irregular forces, and coach others to do the same. These effects will hurt the Army’s credibility with partners that may face the same threats in their homelands. Additionally, the Army’s strong tendency toward optimism and a can-do attitude can harm it in the public domain. Year after year of Army commanders reporting progress in the war on terrorism generally and in building the Iraqi Army and ANA in particular do not wash with the reality that unfolded in both countries in a matter of days. It remains to be seen what damage these events will do to US civil-military relations, but comparisons to Vietnam are inevitable. The Army must hold sacred the trust the American people have in it.

Temptation to retreat from irregular warfare. The Army has traditionally thought of itself as a conventional maneuver force that closes with and destroys the enemy.13 Irregular warfare is often viewed within the Army, paradoxically, as either just a set of easy, lesser-included tasks subordinate to conventional warfare or as extremely hard, demanding missions that detract from conventional warfighting proficiency.14 For this reason, in part, the Army has made huge efforts in the past few years to rebuild its conventional warfighting proficiency and to focus on preparing for possible future conflicts with China and Russia.15 To be certain, preparing for the conventional force threats posed by states such as China, Russia, North Korea, and Iran is prudent. But thinking ahead about the future of warfare and imagining how to integrate the latest technologies for waging it are also prudent. Nevertheless, high-tech, conventional maneuver warfare on the open battlefield has been the small exception in US combat history. The layered, vexing challenges of irregular warfare and internal conflict have been the persistent norm. One day, the Army may have to fight a conventional force, but it will certainly fight an irregular one.

The Army must not divest itself of the highly perishable knowledge and unique skill sets it should have built over the last 20 years. Unfortunately, the decision to shut down its University of Foreign Military and Cultural Studies (also known as “Red Teaming University”) at Fort Leavenworth, to gut its Peacekeeping and Stability Operations Institute at Carlisle Barracks, and to fold the US Army Africa headquarters into the US Army Europe headquarters are not hopeful signs.16 In the summer of 2014, the chief of staff of the Army established the Operation Enduring Freedom Study Group to examine the history of the Army’s involvement in Afghanistan, from 2001 to 2014. The Army must allow this work to continue and publish the group’s findings. And the Army must actively share the findings instead of shunning them as it has done with its own published history of the Iraq War.17 Similarly, the Army must not allow Barry M. Stentiford’s history of Operation Enduring Freedom – Philippines to remain an overlooked work on a forgotten campaign.18

Balancing conventional and special operations force (SOF) posture and operations. Though the Army is rigging itself for future conventional war with China and Russia, it has also made substantial investment in its structure for training other nations’ armies. Security force assistance brigades (SFABs) and the accompanying Security Force Assistance Command (SFAC) at Fort Bragg are a recognition, rightly, that the Army’s success in future conflict will necessarily be bound with the ability of its partners to fight effectively alongside it.19 But in creating the SFABs and SFAC, the Army has muddied the water on the role of its special operations forces (SOF) in training indigenous forces.20 The Army must think critically about the relationship between SFABs and SOF and clarify it.

More broadly, the Army needs to reconsider how best to integrate conventional forces and SOF during operations. The Army must acknowledge and build upon the demonstrated warfighting power of combined SOF, air power, limited conventional forces, and indigenous forces. This force mix has successfully defeated the Taliban, Saddam Hussein’s Iraqi Army, Muammar al-Qaddafi’s army in Libya, and Islamic State of Iraq and Syria forces. The Army should be ready and willing to execute this type of campaign again. Likewise, the Army should be capable of assisting partners in Europe with resisting Russian-sponsored, unconventional warfare proxies.

Reexamining professional military education. The development of campaign planners, operational artists, and strategic thinkers and leaders will be of critical importance to the Army’s success in every future endeavor in peace and war. Soon after the debacle of the Vietnam War, a cadre of emerging, senior leaders in the Army posited some of the military failure in Vietnam was owed to the poor education of its young, field-grade officers.21 The School of Advanced Military Studies (SAMS) was created in 1981 to give the most promising officers an additional year of education beyond the year already provided at the Command and General Staff College. The SAMS curriculum has shifted over the past 40 years, but it has maintained a central focus on military planning, doctrine, and operational art and design. The curriculum has also sought to impart mental tools to help commanders and their staffs think deeply and more critically in hopes of avoiding the pitfall of confusing activity with actual progress—to devise campaigns that could achieve solutions to the true military problems facing the Army.

In 1997, the Army created the Functional Area 59, or strategist, career field to ensure it had a cadre of officers skilled in linking operational campaigns with strategy and national policy aims. The Army established the Basic Strategic Art Program in 2003 to formally educate and initiate its strategists. Since 1901, the US Army War College has educated colonels for service as senior leaders and general officers. For the past couple of decades at least, the Army has also had formal programs dedicated to the education of its general officers. (Since 2017, the Army War College’s Advanced Strategic Education Program has managed these programs.) Thousands of officers have graduated from these schools and programs since 9/11, with many going on to serve and command as colonels and generals in critical positions throughout the Army. Did any of these programs improve the Army’s performance in Iraq or Afghanistan? With so many officers with advanced military educations, how did the Army get things so wrong in both places? These weighty questions demand serious reflection and study.

The Army alone does not bear responsibility for the course of events since 9/11. The Army did not make national policy decisions that had enormous impacts on campaigns on the ground. The Army did not operate alone in these conflict zones. Rather, the Army worked with a wide range of US government agencies; the rest of the services in the US Joint Force; and allies, partners, and host-nation forces. Nor have all outcomes been bad. Special operations forces have successfully disrupted Islamist militants in the Philippines and Africa, al-Qaeda’s global reach is greatly diminished, and the Islamic State in Iraq and Syria is a shadow of its once-fearsome self. Still, the Army was the face of the so-called war on terrorism, and the service must not turn its back on the past 20 years. These experiences and this history will reverberate through time and shape the future of the Army far more than anyone can appreciate today.

  1. “Islamic State & Predecessor Groups,” Combating Terrorism Center at West Point, n.d.,; and Ivana Kottasová et al., “US Troops and Afghans Killed in Suicide Attacks outside Kabul Airport,” CNN , August 26, 2021, /index.html.
  2. Richard L. Kugler, Michael Baranick, and Hans Binnendijk, Operation Anaconda: Lessons for Joint Operations (Washington, DC: Center for Technology and National Security Policy, March 2009), 8–19; and US Senate Committee on Foreign Relations, Tora Bora Revisited: How We Failed to Get Bin Laden and Why It Matters Today, S. Prt. 111-35 (Washington, DC: US Government Publishing Office, November 30, 2009).
  3. John F. Sopko, What We Need to Learn: Lessons from Twenty Years of Afghanistan Reconstruction (Arlington, VA: Special Inspector General for Afghanistan Reconstruction, August 2021).
  4. Brian Neumann, Lisa Mundey, and Jon Mikolashek, Operation Enduring Freedom, March 2002 – April 2005, CMH Pub 70-122-1 (Washington, DC: US Army Center of Military History, 2013), 26.
  5. DoD, Enhancing Security and Stability in Afghanistan (Washington, DC: DoD, December 2020), 59.
  6. See John F. Sopko, Quarterly Report to the United States Congress (Arlington, VA: Special Inspector General for Afghanistan Reconstruction, July 30, 2021); and Jonathon Schroden, “Afghanistan’s Security Forces versus the Taliban: A Net Assessment,” CTC Sentinel 14, no. 1 (January 2021): 20–29.
  7. Sayed Sarwar Amani and Andrew MacAskill, “Desertions Deplete Afghan Forces, Adding to Security Worries,” Reuters, January 18, 2016, -army-desertions/desertions-deplete-afghan-forces-adding-to-security-worries-idUSKCN0UW1K3.
  8. Sopko, Quarterly Report, 84.
  9. See Sanjeev Miglani, “Afghan Forces Need Reading Lessons Before Security Transfer,” Reuters, June 22, 2012, /afghan-forces-need-reading-lessons-before-security-transfer-idUSBRE85L05V20120622.
  10. Javid Ahmad, Dress Like Allies, Kill Like Enemies: An Analysis of ‘Insider Attacks’ in Afghanistan (West Point, NY: Modern War Institute at West Point, April 4, 2017).
  11. Chris Mason, The Strategic Lessons Unlearned from Vietnam, Iraq, and Afghanistan: Why the Afghan National Security Forces Will Not Hold, and the Implications for the US Army in Afghanistan (Carlisle, PA: Strategic Studies Institute, US Army War College Press, 2015).
  12. Justin Sink and Jennifer Jacobs, “Biden Says Taliban in ‘Existential Crisis’ over Role in World,” Bloomberg, August 19, 2021,
  13. “Infantry Heritage,” US Army Fort Benning, updated December 18, 2018, https://www
  14. Robert O. Work, Irregular Warfare (IW), DoD Directive 3000.07 (Washington, DC: DoD, updated May 12, 2017).
  15. See for example Brad Lendon and Ellie Kaufman, “US Military Gets ‘Laser Focused’ on Keeping Up with China,” CNN, June 11, 2021,; and Patrick J. Donahoe and John Spencer, “A Status Check on the Army’s Preparation for the Next War,” Modern War Institute at West Point, July 6, 2021,
  16. Bryce Hoffman, “US Army Moves to Close Red Teaming University,” Forbes, October 26, 2020,; Peacekeeping and Stability Operations Institute leadership, interview by the author, June 2020; and US Army Public Affairs, “US Army Europe and Africa Commands Consolidate,” US Army, November 20, 2020, /article/241094/u_s_army_europe_and_africa_commands_consolidate.
  17. Joel D. Rayburn et al., The US Army in the Iraq War, Volume 1: Invasion-Insurgency-Civil War, 2003–2006 (Carlisle, PA: US Army War College Press, 2019); and Joel D. Rayburn et al., The US Army in the Iraq War, Volume 2: Surge and Withdrawal, 2007–2011 (Carlisle, PA: US Army War College Press, 2019).
  18. Barry M. Stentiford, Success in the Shadows: Operation Enduring Freedom – Philippines and the Global War on Terror, 2002–2015, ed. Diane R. Walker (Fort Leavenworth, KS: Combat Studies Institute Press, 2018).
  19. Andrew Feikert, Army Security Force Assistance Brigades (SFABs), Report No. IF10675 (Washington, DC: Congressional Research Service, updated July 1, 2021).
  20. Ivor Wiltenburg and Martijn Kitzen, “What’s in a Name? Clarifying the Divide between Military Assistance and Security Force Assistance,” Small Wars Journal, November 9, 2020,
  21. Former director of and student at the School of Advanced Military Studies, interview by the author, July 2005.

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