November 19, 2020

Back to the Future: Transforming the U.S. Army for High-Intensity Warfare in the 21st Century

The Bottom Line

  • The U.S. Army is in the middle of a major transformation—shifting its focus back to high-intensity warfighting against peer competitors in the western Pacific and Europe after two decades of irregular wars in the Middle East and Central Asia.
  • Although the Army has made significant progress in driving forward this transformation, the next steps in this process will be critical as the Army embarks on a major force structure redesign effort.
  • As the Army undertakes this effort, it should keep in mind several important considerations that have doctrinal, material, and organizational implications. These considerations include figuring out how to fight inside adversary anti-access/area denial (A2/AD) environments early in a conflict; experimenting with new tactical force designs for a war with China in the western Pacific; prioritizing the development of new sustainment concepts and forces; and potentially having active infantry brigade combat teams (IBCT) serve as a source of force structure trade space.


Five years ago, the U.S. Army stood at a crossroads. After a decade and a half of grueling, irregular wars in the Middle East and Central Asia, the Army’s traditional proficiency in large-scale, combined-arms maneuver warfare had atrophied. Its equipment was outdated, broken, or both, and its soldiers were worn out. The specter of sequestration loomed, and the Army faced a shrinking budget and reductions in end strength. At the same time, the strategic situation confronting the United States had dramatically changed. While the United States was distracted by the wars in the Middle East and Central Asia, Chinese military modernization had continued apace, and Russia had reemerged as a conventional threat in Europe. Moreover, the combination of emerging technologies and adversaries’ employment of innovative operational approaches threatened to undermine the traditional American way of war.

The Army confronted a similar situation in the aftermath of the Vietnam War. And much like the late 1970s and early 1980s, the Army responded by embarking on a generational transformation to shift its focus back to preparing for high-intensity warfare with peer competitors in Europe and the western Pacific. Since 2015, the Army has made significant institutional, doctrinal, organizational, and material progress in driving this transformation forward. The Army has created Futures Command; moved out on developing a new operational concept, multi-domain operations (MDO); launched a major force structure redesign initiative; and pursued an ambitious modernization plan that has been resourced, in part, through self-imposed cuts to nonpriority programs.

The Army’s transformation remains a work in progress and potential pitfalls still lurk on the horizon.

The Army should be commended for how far it has come over the last five years, particularly in terms of modernization, and the pace of change has only accelerated since the publication of the 2018 National Defense Strategy. But the Army’s transformation remains a work in progress and potential pitfalls still lurk on the horizon. As the Department of Defense embarks on developing the next defense strategy and the Army charts its path forward, several important considerations should be kept in mind. These considerations include figuring out how to fight inside adversary A2/AD early in a conflict, experimenting with new force designs for a war with China in the western Pacific, prioritizing the development of new sustainment concepts and forces, and the potential for active IBCTs to serve as a source of force structure trade space. Each of these considerations could have significant doctrinal, material, and organizational implications for the Army’s effort to remake itself into a 21st-century fighting force.

Figure Out How to Fight Inside Adversary A2/AD Early in a Conflict

Faced for the first time in a generation with nuclear-armed peer competitors as its principal security challenge, the United States has increasingly shifted toward a deterrence-by-denial and defense-by-denial approach centered on blunting adversary aggression at the outset of a conflict. But blunting aggression cannot be accomplished solely from standoff distances, nor can the U.S. military afford to wait until the adversary’s A2/AD capabilities are significantly degraded before coming to grips with attacking forces. Forward positioned U.S. forces, including Army forces, will need to fight inside highly contested environments early in a conflict. This type of role has strong antecedents in the Army’s history. The last time the United States faced a significant peer threat, during the late Cold War, the Army’s primary mission was to fight on highly lethal battlefields along the inner German border to keep the numerically superior Soviet army at bay. In fact, the motto of the Army’s principal doctrine at the time, AirLand Battle, was to “fight outnumbered and win.”

The Army’s emerging doctrine, MDO, recognizes the importance of having lethal and resilient forces capable of fighting within adversary A2/AD early in a conflict. It emphasizes the need for forward-postured and rapidly deploying forces to be able to deny an adversary fait accompli, stating that in a conflict, these forces must “immediately contest the enemy attack by enemy maneuver forces.” But on future battlefields saturated with adversaries’ massed precision fires and electronic warfare capabilities, this is easier said than done. MDO, which primarily focuses on how to degrade adversaries’ A2/AD capabilities over time, is short on details that explain how to do so. Moreover, the increased lethality and vastly expanded depth of future battlefields presents a more difficult challenge than Army forces faced in the late Cold War. Preparing for 21st-century combined-arms maneuver by simply dusting off AirLand Battle will not be enough.

Preparing for 21st-century combined-arms maneuver by simply dusting off AirLand Battle will not be enough.

The Army needs to prioritize its conceptual development efforts on how these inside ground forces will fight and survive within highly contested environments to degrade, delay, and deny enemy maneuver forces early in a conflict. This shift in focus is critical not only because it will require doctrinal innovation, but also because the resulting operational and tactical concepts will almost certainly have major implications for the Army’s capability development, force structure, and posture. In short, a force designed to fight outnumbered in the thick of adversaries’ A2/AD early in a conflict will undoubtedly need to look, posture, and operate differently than one designed to degrade A2/AD before launching a counterattack.

Experiment with New Tactical Force Designs for a War with China in the Western Pacific

There is an old saying the Army likes to use when comparing itself to the other services—the Army isn’t platforms, its people. The truth is, however, that the Army is formations. That is, those combinations of people, capabilities, and organizations that make up the Army’s warfighting force structure. These formations are the means through which the Army fights and will therefore be the ultimate manifestations of the Army’s transformation efforts. Accordingly, the Army has launched the AimPoint Force Structure Initiative to design the Army of the future.

The Army has long neglected its echelons above brigade (EAB) formations. These formations are critical to the ability of the Army to execute a high-intensity fight, but have received short shrift over the past two decades, which have been dominated by irregular wars. Already, the Army has taken some steps to address these gaps by standing up additional EAB enablers, such as fires and air defense units, as well as experimenting with new EAB formations, such as the multi-domain task force and theater fires command. The AimPoint initiative is intended to build on this progress and will focus primarily on redesigning and rebuilding the Army’s EAB formations. Moreover, senior Army leaders have stated that the AimPoint initiative will explore creating tailored EAB force structures for each theater. The United States can almost certainly not afford one Army for Europe and another for the Pacific, but given the significant difference between the two theaters in both geography and the Army’s role, at least some regional bifurcation of force structure is likely necessary.

At the same time, however, senior Army leaders have indicated that the initiative will likely not result in much change or regional variation at brigade combat team (BCT) level or below. Although a force centered around divisions comprised of maneuver-centric BCTs at the tactical level makes sense for Europe—where combined-arms maneuver warfare will still be a core element—it is less clear how relevant BCTs will be in a war with China on the maritime-centric terrain of the western Pacific. Furthermore, the Army is currently developing a series of cross-domain capabilities, such as anti-ship missiles, that will enable Army forces to undertake new missions that are outside of its traditional role. Unless the Army envisions contributing to these new missions only in a niche strategic capacity, standing up a theater-level multi-domain task force will likely not be enough.

The Army needs to rethink how it is organized to fight a conflict in the western Pacific from top to bottom. As such, the Army should explore and experiment with new tactical-level formations designed specifically for combat in the western Pacific, similar to what the Marine Corps is pursuing with the recently announced littoral regiment concept. Rather than being centered on combined-arms maneuver, these new formations could be built around cross-domain fires and contain novel combinations of capabilities to enable distributed Army forces to contribute to sea, air, and information denial operations along the First and Second Island Chains. Once the Army has settled on an appropriate force design for these new formations, the question of how to resource them will remain. The Army could create these formations as ad hoc task forces at the time of need, drawing the building blocks from within existing formations. However, the Army should also examine organizing, training, and equipping these formations as permanent, purpose-built units, as this will allow these formations to build cohesion and preparedness to execute these new missions. While the United States may not be able to afford an entire second Army just for the Pacific, tailoring at least some portion of its forces for that theater is just as sensible for tactical combat forces as it is for EAB headquarters and enablers.

Don’t Forget about Sustainment

When it comes to concept development or force design, combat operations tend to dominate the conversation. But it is the critical enabling functions that form the backbone of U.S. military might. In particular, sustainment is not only a core Army mission, but essential to how the U.S. military wages war. Without its mastery of and capacity for sustainment operations, the U.S. military could not get to the fight, nor maintain itself once there. On 21st-century battlefields, however, the U.S. military’s ability to conduct sustainment operations is increasingly challenged. New warfighting concepts focused on employing geographically distributed forces, especially across the vast distance of the Pacific, will likely strain existing sustainment force structure. At the same time, legacy sustainment concepts optimized for efficiency are imperiled by long-range precision fires that will enable adversaries to strike key nodes across the entire breadth and depth of a theater of operations.

Without its mastery of and capacity for sustainment operations, the U.S. military could not get to the fight, nor maintain itself once there.

Overcoming these emerging challenges will require doctrinal, material, and organizational innovation. Efforts to reduce combat forces’ demand for sustainment are commendable and should be continued and expanded. But even with these efforts, combat forces will still need to be resupplied and to undergo maintenance, all while under multi-domain attack. And given the Army’s primary role in not just sustaining itself, but also in supporting the larger joint force, it should not neglect developing the concepts, capabilities, and force structure needed to enable sustainment operations to succeed on highly contested future battlefields.

Consider IBCTs as a Source of Trade Space

Ensuring that Army forces have the right structure for fighting inside adversary A2/AD, developing new tactical formations designed for combat operations in the western Pacific, reversing 20 years of neglect for EAB forces, and augmenting sustainment force structure will all incur major manpower costs. The Army, however, is unlikely to see any major increases to end strength. Even if it did, without a corresponding plus-up in budgetary resources, the increased costs stemming from personnel growth would crowd out funding for other priorities such as the Army’s ambitious modernization efforts. As a result, the Army will likely need to look to trades within its existing force structure, rather than to new growth to create new formations.

As the Army considers elements within its force structure that could potentially serve as trade space, it should take a hard look at its inventory of IBCTs. During the wars in Iraq and Afghanistan, the Army shifted its active BCT inventory to include a higher percentage of IBCTs than had historically been the norm. Although the Army recently converted one IBCT into an armor brigade combat team (ABCT), IBCTs still comprise over 40 percent of the active BCT inventory. But IBCTs have only limited utility in high-intensity conflicts in Europe, and, as noted above, BCTs of any type are likely not the most appropriate formations for a war with China in the western Pacific. In Europe, IBCTs can play a role in defending complex terrain such as urban or mountainous areas. But even with the Army’s plan to augment IBCT’s capability with the mobile protected firepower vehicle—essentially a light tank—and the ground mobility vehicle, they will still lack the mobility, firepower, and protection to conduct combined-arms maneuver in a conflict with Russia. Moreover, the Army already possesses seven Stryker brigade combat teams (SBCT) in the active force, light armor formations with a comparable number of dismounted infantrymen to IBCTs, for when it needs to augment its ABCTs in combined-arms maneuver warfare.

The Army will likely need to look to trades within its existing force structure, rather than to new growth to create new formations.

Given these considerations, at least some portion of the Army’s active IBCT inventory is expendable. Therefore, the Army should explore cutting some of its active IBCTs to create trade space to enable it to make desired force structure changes. Eliminating these IBCTs will serve to free up manpower that can be used to increase the Army’s inventory of other BCT types, such as the ABCTs that will be in high demand in a conflict with Russia, to create new tactical-level combat formations for the Pacific, or to grow its EAB force structure. As a hedge against the need for large amounts of light infantry formations, the Army can still rely on the National Guard, where IBCTs comprise nearly 75 percent of the BCT inventory.


Five years into its transformation from a force focused on irregular warfare in the Middle East and Central Asia to one prepared to wage high-intensity war against peer adversaries in Europe and the western Pacific, the Army has made significant progress. But the path it charts forward from here will be critical, as the decision the Army makes will have profound implications for concepts, capabilities, and force structure. With that in mind, the Army should focus its efforts on figuring out how to fight inside adversaries’ A2/AD environments, exploring force designs that account for differing environments and roles between theaters, emphasizing critical enablers like sustainment as much as combat forces, and looking to IBCTs as potential trade space to resource force structure changes.

About the Author

Billy Fabian is an Adjunct Senior Fellow at CNAS and a Senior Analyst at Govini. He has previously served as Research Fellow at the Center for Strategic and Budgetary Assessments; a Senior Strategic Analyst in the Department of Defense, where he worked on the 2018 National Defense Strategy; and an infantry officer in the U.S. Army.

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From July to December 2020, CNAS will release new papers every week on the tough issues the next NDS should tackle. The goal of this project is to provide intellectual capital to the drafters of the 2022 NDS, focusing specifically on unfinished business from the past several defense strategies and areas where change is necessary but difficult.


The Next Defense Strategy

About this commentary series By statute, the Department of Defense (DoD) must deliver a new National Defense Strategy (NDS) to Congress in 2022. And CNAS is here to help. From...

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  1. Chris M. Dougherty, “Why America Needs a New Way of War” (Center for New American Security, 2019),
  2. Jen Judson, Army Futures Command is ready for prime time,” Defense News, July 17, 2019,; U.S. Army, 2019 Army Modernization Strategy: Investing in the Future,; Jen Judson “Army’s ‘night court’ finds $25 billion to reinvest in modernization priorities,” Defense News, October 8, 2018,
  3. For example, see Elbridge Colby, “How to Win America’s Next War,” Foreign Policy, May 5, 2019,; Michele A. Flournoy, “How to Prevent a War in Asia: The Erosion of American Deterrence Raises the Risk of Chinese Miscalculation,” Foreign Affairs, June 18, 2020,
  4. Billy Fabian, “Overcoming the Tyranny of Time: The Role of U.S. Forward Posture in Deterrence and Defense,” (Center for New American Security, 2020),
  5. U.S. Army, TRADOC Pamphlet 525-3-1, The U.S. Army in Multi-Domain Operations 2028, Ch 3,
  6. The current version of MDO devotes just one paragraph to contesting enemy maneuver forces. See The U.S. Army in Multi-Domain Operations 2028, 33.
  7. Congressional Research Service, Andrew Feickert, The Army’s AimPoint Force Structure Initiative, CRS Report No. IF11542 (May 8, 2020),
  8. Feickert, The Army’s AimPoint Force Structure Initiative.
  9. Sydney J. Freedberg Jr., “The Army Rebuilds Artillery Arm for Large Scale War,” Breaking Defense, April 27, 2020,
  10. Devon Suits, “Futures and Concepts Center evaluates new force structure,” Army News Service, April 22, 2020,
  11. Freedberg Jr., “The Army Rebuilds Artillery Arm for Large Scale War.”
  12. David Axe, “You’re So Dead: Marines and Army Now Have Anti-Ship Missiles,” National Interest, February 4, 2020,
  13. Philip Athey, “Corps to begin 3-Year Marine Littoral Regiment experiment using Hawaii Marines,” Marine Corps Times, September 22, 2020,
  14. Thomas G. Mahnken, Travis Sharpe, Billy Fabian, and Peter Kouretsos, “Tightening the Chain: Implementing a Strategy of Maritime Pressure in the Western Pacific,” Center for Strategic and Budgetary Assessments, 2019,
  15. For example, Sydney J. Freedberg Jr., “Do Soldiers Dream of Electric Trucks,” Breaking Defense, April 22, 2020,
  16. Mark Cancian and Adam Saxton, “2021 Budget Spells The End of US Force Exanasion,” Breaking Defense, February 14, 2020,
  17. “The 2020 Federal Scorecard: High-Intensity Warfare Edition,” Govini, 2020,
  18. The Army’s current active inventory consists of 11 ABCTs, seven SBCTs, and 13 IBCTs. Todd South, “The Army is converting two BCTs as it beefs up its fighting force for the next big war,” Army Times, September 20, 2018,
  19. Congressional Research Service, Andrew Feickert, Infantry Brigade Combat Team (IBCT) Mobility, Reconnaissance, and Firepower Programs, CRS Report No. R44968, (Updated July 8, 2019),
  20. The Army’s current National Guard inventory consists of five ABCTs, two SBCTs, and 20 IBCTs. South, “The Army is converting two BCTs as it beefs up its fighting force for the next big war.”
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