Meeting the Challenge of Large-Scale Combat Operations Today and Tomorrow

Lt. Gen. Michael D. Lundy, U.S. Army

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While our Army learned invaluable lessons over the last seventeen years of limited contingency operations, the experience culturally imprinted a generation of Army leaders for one type of warfare. An increasingly volatile operational environment (OE) characterized by great power competition demands that our Army adapt to the realities of a world where large-scale ground combat against a peer threat is more likely than at any time in recent history. Preparing for the most lethal and challenging threats to our nation warrants continued bold changes in how we man, equip, train, and employ Army forces, especially at echelons above brigade.

Over the last decade and a half, our peer and near-peer competitors studied us as we optimized our force for limited contingency operations. They fielded more professional forces with advanced capabilities, improved training, and combined arms formations designed to contest us and our multinational partners across all of the domains. They adapted, improved, and continued to advance. In addition to violent extremist organizations with global reach, the current and future strategic environment is defined by a revanchist Russia, an expanding China, a rogue North Korea, and a calculating Iran.1 It demands a U.S. Army prepared to continually (and persistently) shape the security environment to our advantage, deter adversary aggression through strength, and when necessary, prevail in large-scale ground combat as a member of the Unified Action team.2 We are in great power competition today, and with competition, conflict is always a risk—this is not just a problem for tomorrow’s leaders.

Success in large-scale combat operations against peer threats requires that we continue to evolve from a focus on predictable rotational deployments for stability operations to expeditionary operations in contested domains with few indications or warnings. With the renewed focus on readiness to meet the challenges of great power competition or conflict, we must continue to master the required skills to enable the Army’s four strategic roles for the joint force: shaping security environments, preventing conflict, prevailing in large-scale ground combat, and consolidating gains to make the temporary permanent.

For decades the United States has enjoyed uncontested or dominant superiority in every operating domain. We could generally deploy our forces when we wanted, assemble them where we wanted, and operate how we wanted. Today, every domain is contested—air, land, sea, space, and cyberspace.

—Jim Mattis, Secretary of Defense3

There will always be tension between readiness for the worst case of large-scale ground combat and the requirements of limited contingency and shaping operations the Army conducts daily around the world. These adjustments will be at least as difficult as those made by our predecessors after Vietnam. Unlike post-Vietnam, however, as we make these adjustments, we cannot eschew the lessons of Iraq and Afghanistan. Retaining the hard-won lessons learned within our doctrine and training while also expanding our expertise in the required tactics, techniques, and procedures for large-scale ground combat is essential.


The Army is on the right path to developing leaders and units with the requisite skills and attributes to prevail in large-scale ground combat against peer threats. Our combat training centers have increased the intensity and realism of our unit decisive action rotations, unit home station training occurs at higher operational tempo and under more demanding conditions, and we have made significant adjustments to the rigor and focus of our professional military education and functional training.4 Mastering the skills and experiences acquired during training, education, and operations requires repetition. Sustaining and improving what we are doing now is our challenge. Preparing and certifying leaders, hardening the force for the chaos and lethality of large-scale combat operations, and reorganizing our formations while fielding advanced technologies and new equipment requires an enduring and persistent focus.

To drive this cultural change, we renewed the focus on combined arms operations in large-scale ground combat with our newest doctrine, Field Manual (FM) 3-0, Operations. FM 3-0 is the Army’s capstone tactics manual for execution of unified land operations against peer and near-peer threats in contested multi-domain environments.5 It serves as a pivot point to steer the Army toward both persistent competition below armed conflict and, when necessary, armed conflict against highly lethal and adaptive peer and near-peer enemies. FM 3-0 does not disregard what we’ve learned over the last seventeen years. In fact, it reinforces and provides deeper context to the value and necessity of persistently competing, prevailing, and consolidating gains across the range of military operations and the conflict continuum.6 To address the continuum, FM 3-0 is organized in accordance with the Army’s four strategic roles it uniquely performs for the joint force: shape the security environment, prevent conflict, prevail in large-scale ground combat, and consolidate gains.7 It emphasizes that maintaining positions of strategic advantage requires enduring outcomes favorable to U.S. interests.

FM 3-0 acknowledges we will not always enjoy the full domain superiority we have come to expect since the early 1990s. It recognizes that, with fewer forward-deployed forces than just twenty years ago, our force posture and activities must be optimized to successfully compete below the threshold of armed conflict. We do this by seeing, understanding, and preparing the environment; continuously setting the theater; conducting cyber and information operations; deploying rotational forces; and building readiness. By improving our own readiness for armed conflict and that of our partners, we maintain access and demonstrate the capability and will to win as part of a larger team. Multinational and joint operations are essential to this approach. How we build capacity and maintain access while denying adversaries positions of cognitive, virtual, temporal, and physical advantage are increasingly important to a largely CONUS-based Army.8 To assure allies, we must be able to deter. To deter, our adversaries must believe we will prevail.


FM 3-0 addresses the challenges of the current and near-term multi-domain operational environments and guides our approach to winning against all possible competitors. Aspects of emerging multi-domain concepts have been integrated into FM 3-0 including space, cyber, electronic, and information warfare. These capabilities reinforce our combined arms approach to the traditional aspects of warfare in the land, air, and maritime domains. FM 3-0’s new operational framework provides an expanded physical, virtual, cognitive, and temporal perspective to account for the multi-domain extended capabilities of friendly and threat forces. The physical and temporal considerations pertain to space and time, while the cognitive considerations apply to enemy decision-making, enemy will, and population behavior. The virtual considerations address friendly and threat cyberspace activities, cyber-enabled capabilities, and the entities that exist in cyberspace. Collectively, these considerations allow commanders and staffs to better converge multi-domain capabilities at echelon with the tempo and intensity necessary to present the enemy with multiple dilemmas from positions of tactical, operational, and strategic advantage.9

Central to the challenge of evolving the Army’s culture is reenabling our division, corps, and theater armies to operate and fight as combat formations. Beginning with a perception in the mid-to-late 1990s of a reduced risk of great power conflict and exacerbated by ongoing limited contingency operations, the Army transformed from a division-based to a brigade-based modular force. As a result, echelons above brigade (EAB) transformed from highly-capable warfighting formations to headquarters that could be force-tailored with warfighting “modules” to accomplish a variety of missions. Over time, the separate modular components were further optimized for the prevailing fight—counterinsurgency and other stability operations.10 When coupled with heavy reductions during directed downsizing, EAB headquarters became much less capable of supporting anything more than limited contingency operations. While required at the time, the degradation of echelons above brigade formations and their capabilities significantly reduced the Army’s ability to meet the entirety of its primary function—to execute prompt and sustained land combat to defeat any threat throughout the range of military operations.

As we adapt today’s EAB headquarters into warfighting formations in doctrine, we also keep an eye on tomorrow through future concept work. The “U.S. Army Concept for Multi-Domain Combined Arms Operations at Echelons Above Brigade, 2025-2045” provides the foundation for the experimentation and development of future EAB capabilities. Informed by the Joint Warfighting Assessments, Mission Command Training Program lessons learned, the Multi-Domain Task Force pilot, and numerous battle lab and Army level experiments, the EAB concept has been continuously refined to identify the most critical doctrine, organization, training, materiel, leadership and education, personnel, facilities, and policy requirements for future EAB formations. This concept work has revealed key foundational requirements at each EAB echelon to defeat peer threats during both competition and conflict in the future.

Future Theater Armies

Uniquely-tailored future theater armies maintain enduring operational initiative. The theater army is unique as it is the only persistent Army echelon for a geographic area of responsibility. As an Army Service component command, all theater armies share the same basic set of theater management tasks distilled to five primary categories: setting conditions in the theater for the employment of landpower (setting the theater), Army support to theater security cooperation, Army support to other services, administrative control over all Army forces in the area of responsibility, and operational control and sustainment support of any assigned or attached Army forces until the combatant commander attaches those forces to a subordinate joint command.11 To shape the security environment, prevent conflict, and, when necessary, prevail in large-scale combat operations in peer-adversary theaters, theater armies require greater operational warfighting organic capabilities. These capabilities include threat-specific intelligence, surveillance, and reconnaissance; electronic warfare; air and ballistic missile defense; cyberspace, space, information warfare capabilities; and hardened command and control. Theater armies enable freedom of movement during transitions from competition to armed conflict and back. In the future OE, theater armies are central to winning in competition below armed conflict and ensuring that Army and coalition forces can operate from distributed and protected positions of advantage during armed conflict.12

Future Field Armies

Threat-focused future field armies provide credible deterrence, execute multi-domain competition against peer threats, and enable a rapid transition to and execution of large-scale ground combat operations (LSGCO). While all theaters require an operational capability, some theaters have adversaries that present enough risk of LSGCO that they require an additional standing echelon to manage specific operations within the area of responsibility and then transition rapidly to a land component command. Historically, this has been a field army commanding two or more corps. A field army is employed to relieve the operational burden on the theater army when attention to a specific operation in a subordinate geographic area would detract from the theater army’s ability to support strategic objectives in the theater as a whole. The field army is forward stationed to account for the higher probability of LSGCO or other vital geopolitical considerations that may require partner assurance. It is required in areas of persistent, intense competition with a peer threat capable of rapidly transitioning to large-scale land combat. The field army can serve as the foundation for a joint task force, joint forces land component command, or merge into a standing—but underresourced—alliance headquarters. A standing field army allows rapid transition from competition to conflict. The presence of a field army changes the threat’s risk calculus and helps prevent conflict or sets the conditions for success in LSGCO where multiple corps are required to defeat a peer enemy.


Future Corps

The future corps is the linchpin of EAB versatility and agility. The corps of tomorrow must be the most versatile echelon in the Army because no other echelon can. Since future theater armies are tailored to their respective theaters and operational support of Army missions defines their functions, their versatility is limited. Similarly, a future field army is sharply focused on succeeding in competition below armed conflict against a specific peer threat within the theater and setting conditions to rapidly transition to armed conflict as a multi-corps land component command. Meanwhile, future divisions maintain an uncompromising emphasis on readiness for the task of integrating multiple brigade combat teams (BCTs) and enabling formations as a highly-lethal, tactical formation to win the close fight during armed conflict. This limits some aspects of versatility at the division level. The future corps, functioning as the link between the operational and tactical levels of war, emerges as the echelon that affords the greatest potential for adaptation in response to the uncertainty of both future threats and the environment. This agility mitigates the operational risk naturally found in warfare when predictions of the future OE frequently fail to match reality.

We want a military, across the board, to be unbelievably lethal and unbelievably dominant, so that no nation will ever challenge the U.S. militarily.

—Gen. Mark A. Milley13

Highly versatile, future Army corps are the U.S. Army’s intermediate tactical warfighting formations for large-scale combat, assigned with redundant capabilities and capacities to see and understand, decide, shape, strike rapidly, and endure. Concept development, experimentation, and lessons learned demonstrate that the most effective future corps organizational design includes assigned military intelligence, multi-domain reconnaissance and security, fires (artillery and air defense), maneuver support, space, cyberspace, information warfare, electronic warfare, sustainment, and aviation formations. These future subordinate formations enable the corps to conduct deep operations physically, temporally, virtually, and cognitively and enable subordinate divisions to dominate the close fight.14 While assigned to the future corps, these capabilities can be task organized to directly support a subordinate division as the main effort.15

Future Divisions

Tactically-focused future divisions shape, dominate, and win the close fight. The division’s role of commanding and sustaining multiple BCTs and enabling formations in tactical operations remains its primary focus and is the crux of the Army’s ability to gain and maintain contact and defeat an enemy maneuver force in violent close combat. This requires future Army divisions to singularly focus on lethal, tactical warfighting; it is the principal tactical echelon above brigade. Future Army divisions must have assigned reconnaissance and security, aviation, fires, maneuver enhancement, and sustainment formations in addition to capable BCTs. When properly force-tailored, postured, and positioned, divisions—along with other echelons above brigade formations—are a powerful, credible, and devastatingly lethal deterrent to any would-be threat.16


Large-scale ground combat is more likely today than at any point since the end of the Cold War. And the risk of great power conflict will likely persist into the distant future. While the last seventeen years of limited contingency and counterinsurgency operations were necessarily brigade-centric, conflict with peer and near-peer threats requires a continued culture shift as well as the optimization of EABs into highly capable divisions, corps, field armies, and theater armies. These EAB multi-domain fighting formations, coupled with requisite training, leader development, and modernization, enable the Army to shape security environments, prevent conflict, prevail in large-scale combat, and consolidate gains to make tactical success strategically enduring—today and tomorrow.


  1. Office of the Secretary of Defense (OSD), “Summary of the 2018 National Defense Strategy of the United States of America” (Washington, DC: Department of Defense, 2018), 1, accessed 16 August 2018,
  2. FM 3-0, Operations (Washington, DC: U.S. Government Publishing Office [GPO], 2017), 1-14–1-15.
  3. OSD, “Summary of the 2018 National Defense Strategy,” 5.
  4. Center for Army Lessons Learned (CALL) Newsletter 17-18, Decisive Action Training Environment at the JRTC, Volume XV: Lessons and Best Practices (Fort Leavenworth, KS: CALL, June 2017).
  5. FM 3-0, Operations.
  6. Ibid., 1-1.
  7. Ibid., 1-14–1-15.
  8. U.S. Joint Chiefs of Staff, “National Military Strategy of the United States of America” (Washington, DC: U.S. Joint Chiefs of Staff, June 2015), 9–10.
  9. Stephen Townsend, “Accelerating Multi-Domain Operations: Evolution of an Idea,” Modern War Institute at West Point (website), 23 July 2018, accessed 16 August 2018,
  10. Stuart E. Johnson et al., A Review of the Army’s Modular Force Structure (Santa Monica, CA: RAND Corporation, 2003).
  11. CALL Special Study 18-29, Theater Army Insights: U.S. Army Europe Operations as a Joint Force Land Component Command: Lessons and Best Practices (Fort Leavenworth, KS: CALL, June 2018).
  12. U.S. Combined Arms Center (CAC), “The U.S. Army Concept for Multi-Domain Combined Arms Operations at Echelons Above Brigade, 2025–2045: Versatile, Agile, and Lethal” (unpublished draft, 14 August 2018).
  13. C. Todd Lopez, “Army ‘Confident in Current Capabilities’ Chief of Staff Says,” U.S. Army (website), 16 April 2018, accessed 16 August 2018,
  14. CALL Handbook, Deep Operations: Lessons and Best Practices (Fort Leavenworth, KS: CALL, March 2018).
  15. CAC, “The U.S. Army Concept for Multi-Domain Combined Arms Operations at Echelons Above Brigade.”
  16. Ibid.

Lt. Gen. Michael D. Lundy, U.S. Army, is the commanding general of the U.S. Army Combined Arms Center and the commandant of the Command and General Staff College on Fort Leavenworth, Kansas. He holds an MS in strategic studies and is a graduate of the Command and General Staff College and the Army War College. He previously served as the commanding general of the U.S. Army Aviation Center of Excellence at Fort Rucker, Alabama, and he has deployed to Haiti, Bosnia, Iraq, and Afghanistan.

September-October 2018