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A Critical Link

The Field Army and Command and Control in LSCO

 

Maj. Brandon J. Schwartz, U.S. Army

 

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From peacekeeping operations in Europe and Africa to the Global War on Terrorism, the U.S. Army did not need field armies to manage its conflicts, so it consolidated headquarters. However, the shift to focus on large-scale combat operations in 2018, punctuated by the full-scale Russian invasion of Ukraine in 2022, changed the Army’s approach to how it fights. As part of this change, the Army elevated its principal tactical warfighting echelon from the brigade to the division and made the corps the focus for joint integration to achieve convergence in multidomain operations.¹ In other words, the echelons above brigade increased in their importance. However, these changes have not extended to the field army echelon. The Army only has one field army, which cannot support operations beyond the Korean peninsula, leaving it with no dedicated capability to command-and-control multi-corps operations.

Yet, the threat of large-scale combat operations looms on the horizon. Against Russia, the United States fears a fait accompli invasion of the Baltic states.² Any response, whether unilateral or with NATO, would likely require multiple corps.³ Against China, multiple corps may be required to defend Southeast Asia following a Chinese invasion of Taiwan.⁴ Even against Iran and North Korea, the United States should be prepared to conduct multi-corps operations to force regime change.⁵ While the regime-change operations are highly unlikely, the Army has a duty to be able to provide policymakers options that allow them to best secure U.S. national interests.⁶

If the United States is serious about preparing for large-scale combat operations and unleashing the full lethality of its corps, then it must reestablish the field army echelon. It is clear that Army force structure has a gap at the land component command level during large-scale combat operations.⁷ There is no dedicated formation to be the land component command for multi-corps maneuver, and current alternatives are unsatisfactory because they overburden the highest echelons of command. For a relatively low cost compared to risk, the Army can create a service-retained field army headquarters to address this shortfall. Besides its operational benefits, creating a field army would contribute to strategic deterrence. As Thomas Schelling succinctly described, deterrence is a combination of capability and will.⁸ By establishing a field army echelon, the Army signals adversaries both the capability and will to execute multi-corps large-scale combat operations.

The Field Army in Multidomain Operations

The Army does not have a dedicated formation to command-and-control multiple corps as the land component command during large-scale combat operations. In 2022, the Army adopted multidomain operations as its operational concept with the publication of Field Manual 3-0, Operations. Multidomain operations deconsolidated the corps and division and also reintroduced the concept of an echeloned Army, which creates strong interdependencies between echelons.⁹ In particular, lower echelons depend on higher echelons to employ critical capabilities to set conditions for success.¹⁰ This implies that effective higher echelons enable leaner, more lethal lower echelons by relieving them of numerous coordination and synchronization tasks. However, it also means that challenges at higher echelons have a compounding effect as they cascade down through lower echelons.

At the top of the Army’s echelonment within a joint operational area is the land component command.¹¹ This role can also become the joint force land component command, depending on circumstances, but I will simplify by focusing on the Army’s internal echelonment to highlight service challenges.¹² Army doctrine states that a corps or a theater army can be the land component command during large-scale combat operations, with the preference being the corps.¹³ However, neither the corps nor theater army are the optimal solution. As a result, the negative ramifications of a suboptimal land component command solution for multi-corps large-scale-combat operations cascade through at least two corps with a combined six divisions and thirty-six brigades. In other words, the stakes are high.

A corps is an ineffective solution as the land component command for multi-corps operations because of strategic risks and lack of staff capacity. The fact is that scarcity is a challenge at this echelon. The U.S. Army only has four corps, of which only two are unassigned or “free agents”—XVIII Airborne Corps and III Armored Corps (see figure 1).¹⁴ With current force structure, planning to use another corps to act as two tactical corps’ field army headquarters creates a few unsavory options. First, the United States could pull a corps away from either the Indo-Pacific or Europe. However, this seems only to invite the type of second-theater adversary opportunism so many rightly fear.¹⁵ This then precludes any corps as a land component command solution for U.S. Central, Southern, and Africa Commands since there would not be any available.¹⁶

Second, the Army could separate a free agent corps’ headquarters from its subordinate structure (see figure 2). However, this creates numerous challenges. The corps would require another formation to act as the corps headquarters for the units that do not deploy with it, thereby simply transferring the inadequate command-and-control problem to another echelon. Also, future large-scale combat will likely be protracted, which means the Army will need to conduct reconstitution operations at all echelons.¹⁷ Thus, the noncommitted free agent corps will have significant training requirements to be prepared to replace the committed corps. These training requirements would compound the effect on the reconstituting corps of losing its organic headquarters. As a result, a separate corps headquarters as land component command is unrealistic because of insufficient capacity.

Due to these shortfalls, the most likely course of action becomes dual-hatting a tactical corps with the land component command role (see figure 3). This is obviously another suboptimal solution. The responsibilities of the land component command would bifurcate the commander and staff’s focus between the corps’ own tactical operations and the synchronization of land operations across the joint operational area. Even with augmentation, the command would be inherently less effective because of its dual focus. This effect compounds in the future operational environment with limited time for decision-making and to exploit opportunities resulting from convergence.¹⁸ Forcing the corps commander to perform both roles simultaneously would be an exceptional risk.

If not the corps, then perhaps the theater army. In fact, joint doctrine states that the theater army is the most likely Army formation to be the joint force land component command during multi-corps large-scale combat operations.¹⁹ However, theater armies cannot effectively act as field armies because of a lack of staff capacity. Over time, the Army has downsized formations at echelons above brigade and consolidated responsibilities in those that remain (see figure 4).²⁰ The ever-shrinking theater army staff is currently manned at approximately four hundred to five hundred and primed for further reductions.²¹

The theater army’s primary role is Army Service component command (ASCC).²² The ASCC role encompasses a broad, complex set of functions and tasks that no other echelon performs. This makes the theater army indispensable to theater operations. Also, most of the ASCC tasks are required by law, which means they cannot be ignored to prioritize others.²³ Being the ASCC includes performing many of the same tasks executed by the Services of Supply (later Communications Zone) during World War II, such as receiving and delivering supplies in theater, control of theater transportation, construction, and evacuation of prisoners and casualties from other commands.²⁴ These requirements will exist in future conflict, again requiring a dedicated command to handle them. The Allies deliberately separated the Services of Supply from tactical command because of its extensive command and staff requirements. During 1944, the ratio between Communications Zone staff to supported soldier was approximately 1:280.²⁵ This means for a fully enabled multi-corps conflict, the theater army would need to be at least 350 personnel to support operations as the ASCC.²⁶ As a result, the relatively small theater army headquarters will be fully consumed with its primary role.

Third Army experienced this challenge during the 2003 invasion of Iraq. Third Army, acting as the Army Service component command and coalition forces land component command for U.S. Central Command, dedicated significant effort to managing the flow of forces into theater and coordinating with Forces Command, Transportation Command, and the Department of the Army. They also had to conduct redeployment planning. This detracted from their ability to synchronize combat operations and plan for consolidation of gains by their subordinate corps formations.²⁷

Recognizing the land component command shortfall, Allies have moved to replace the corps in that role. NATO assessed that they did not have sufficient capability to fight Russia in large-scale combat operations without a dedicated headquarters to control multi-corps maneuver. As a result, they created the multi-corps land component command, which is a field army by a different name.²⁸ This development demonstrates two important points. First, that the Russian threat requires a multi-corps response capability. If the United States is going to continue to prepare to defeat Russia, an admittedly dubious idea at the moment, then it needs a field army. Second, countries with Western-trained and -equipped military forces do not envision the corps as the ideal solution to multi-corps command and control. The creation of the multi-corps land component command should serve as a warning to the United States about its multi-corps command-and-control capability.

This warning from NATO is reinforced by U.S.-led exercises, which also demonstrate the requirement for a dedicated land component command. In the Indo-Pacific, the United States conducted Exercise Yama Sakura in December 2024. This multinational exercise included two corps—the U.S. Army’s I Corps and U.S. Marine Corps’ III Marine Expeditionary Force, which required a land component command.²⁹ The solution? The theater army, U.S. Army Pacific. This is suboptimal for the reasons previously described. Still, Exercise Yama Sakura demonstrated a requirement to command-and-control multiple corps.

In Europe, Exercise Avenger Triad from September 2024 also required a multi-corps command-and-control headquarters. The exercise included three subordinate corps—the U.S. Army’s V Corps, the 1st German-Netherlands Corps, and the 2nd Polish Army Corps.³⁰ U.S. Army Europe and Africa, the theater army, performed as the multi-corps land component command in the exercise. Again, the theater army would not be an optimal solution, especially as the U.S. Army Europe and Africa commander is already dual-hatted as the theater army commander (for two areas of responsibility) and commander of NATO Land Forces Command.³¹ These are just two recent examples of U.S.-led exercises that demonstrate the requirement for a land component command above the tactical corps. A field army would meet this requirement.

In addition to being the land component command, the field army would perform certain service-related functions. Through Title 10, Congress assigns responsibilities to the services with the authority of the law.³² For the secretary of the Army, this includes the standard Title 10 responsibilities commonly referred to as “man, train, and equip.”³³ The secretary then delegates many of those responsibilities to the theater army, who typically divides them with the senior Army commander in a joint operational area, which is the land component command. Doctrine uses the term administrative control to describe this administrative chain of authority. Administrative control is the “direction or exercise of authority over subordinate or other organizations in respect to administration and support.”³⁴ In a large-scale conflict, the field army would be the land component command receiving delegated service authorities through administrative control in addition to the operational requirements of the land component command role.

It is the combination of the land component command role and its inherent service-related responsibilities that would make the field army the commander of Army forces (known as ARFOR). “The ARFOR is the Army component and senior Army headquarters of all Army forces assigned or attached to a combatant command, subordinate joint force command, joint functional command, or multinational command.”³⁵ This means that the field army would assume ARFOR responsibilities for the joint operational area. It also means that ARFOR is the field army’s primary role.

ARFOR responsibilities can be quite extensive. These include numerous types of support to the joint force, such Army support to other Services, common-user logistics, and Army executive agent support. ARFOR also includes Army Title 10 responsibilities for all assigned forces.³⁶ This is significant for multiple reasons. First, the field army would relieve the “dual-hat” corps (as the preferred solution as land component command) from the burden of planning and supervising ARFOR specific tasks. As a result, the corps could then focus on its primary role as tactical headquarters to focus on destroying the enemy’s tactical formations. This is a crucial benefit of establishing a field army. Second, the ARFOR responsibilities have structural implications for the field army. It must be capable of providing service-related functions to the joint force and be able to integrate directly into joint planning and processes. Third, the field army must be provided with adequate formations to meet these responsibilities. For example, a field army requires its own dedicated sustainment formation, such as an expeditionary sustainment command, during combat to meet ARFOR demands.

As an ARFOR, the field army performs numerous functions and tasks that allow the corps to be fully effective. Most important, field armies would set conditions for their corps. The field army would “strike deep into the enemy rear and destroy major fire support means, command posts and supplies, cut lines of communications, and encircle and destroy the enemy combat forces in zone.”³⁷ During the 2003 invasion of Iraq, Third Army focused its efforts on striking the Republican Guards in Baghdad as the corps crossed the initial line of departure in Kuwait.³⁸ This destroyed part of Iraq’s key military capability, thereby enabling the corps’ future fight around Baghdad.

Field armies would also integrate the joint force with the Army’s scheme of maneuver and apportion all domain joint capabilities to the corps.³⁹ This conditions setting is crucial to the success of the corps for multiple reasons. A major reason is that the field army relieves the corps of much of the joint coordination burden, which comes with a host of efficiencies including reduced systems management challenges (i.e., “swivel-chair”) and freedom from participating in many of the joint processes (e.g., the joint force commander’s targeting working group). It also shrinks the commander’s time and space cognitive load, as they can focus on defeating the enemy in the land component command’s close area rather than having to consider the entire joint operational area.

Another critical function of the field army is absorbing area behind the corps and conducting rear operations. Seventh Army’s history from World War II stated, “One of the most important army functions … was the prompt release of combat units from responsibility for newly acquired territory, its administration and its use as a base for operations.”⁴⁰ As a result, field armies conducted extensive rear operations. For example, First Army, during the rapid advance into German territory during World War II, had to “secure thousands of square miles of German occupied territory,” deal with bypassed German forces, and “establish order in the hundreds of German towns and villages which had come under army control.”⁴¹ A modern field army would do the same thing as extensive rear area responsibilities often exceed corps capacity.⁴² Rear operations have historically been a significant effort, but it is even more challenging today with the necessity of decentralizing command posts for survival and the ability for the enemy to strike rear areas from all domains.⁴³ The more the corps have to concern themselves with rear operations and a large rear area, the more that they must diffuse their energy from the close and deep fight.

Establishing a field army also provides the opportunity for the Army to conserve force structure through streamlining and pooling. A constant challenge for the Army in recent years is dealing with soldier scarcity to meet all readiness and modernization demands. To economize force, the Army has streamlined some of its lower tactical echelons. Streamlining limits a unit’s organic structure to only what it needs at all times.⁴⁴ The forces removed through streamlining have then been pooled at higher echelons. Pooling is massing similar type units at higher echelons that lower echelon formations only need occasionally.⁴⁵ This process maximizes combat power at lower echelons and limits the quantity of supporting or enabling forces. The tradeoff is that it further increases interechelon dependencies and the importance of task-organizing for missions.

For example, the Army recently removed brigade engineer battalions (streamlined brigades) and created division engineer battalions (pooling).⁴⁶ This reduced the total number of engineers in brigades, which allowed the divisions to maintain readiness while also allowing the Army to redistribute the saved spaces for modernization elsewhere. This approach enhances lower echelon lethality by relieving lower echelon commanders of management of noncombat forces and enables them to build attack-oriented culture. It also enables the higher echelon commander to weight efforts and manage combat power.

Establishing the field army echelon provides the opportunity to streamline and pool echelons at corps and below. Field armies historically pooled critical resources. For example, First Army in World War II had all army artillery units assigned to an army-controlled field artillery brigade and then allocated them by establishing support relationships.⁴⁷ In this case, the longer-range artillery capabilities that the corps and divisions did not need for daily operations were pulled away from them (streamlining) and managed by the field army commander (pooling), who task-organized them back to the corps for specific missions. World War II field army pooling usually included air defense, engineers, artillery, and infantry and armored divisions.⁴⁸ A field army today could do many of these same activities. Much like the multidomain task forces streamlined some long-range fires from corps and below, a field army presents the opportunity to do something similar with aviation, engineers, military intelligence, and air defense (see figure 5). This would reduce the structural burden at the corps for enabling and supporting forces while enhancing the lethality of the corps by streamlining them into leaner, more agile, and offensive-oriented formations.

Alternative Courses of Action

At this point, a logical question would be “who else could be the land component command for multi-corps operations without creating new force structure?” One possibility is to rely on a joint force headquarters or an existing field army-type solution. Another is to wait until conflict and then build an ad hoc field army. However, those options incur significant risk to mission that outweigh the costs of a field army headquarters.

A joint force headquarters is an ineffective field army headquarters because, like the theater army, they do not have sufficient depth to manage both sets of responsibilities. The most likely candidate to fill the field army role in this option is the combatant command.⁴⁹ However, the combatant commands already have numerous responsibilities across their areas of responsibility, each with a large associated list of operations, activities, and investments.⁵⁰ Like the theater army, many of these activities are required by law and are not performed by any other echelon.

In multi-corps large-scale combat operations, the combatant command would also likely be acting as the joint force commander for the conflict. In that role they would be conducting theater-strategic operations and activities while synchronizing the joint and combined force (see figure 6). Having the combatant command simultaneously act as the field army essentially adds joint force land component command as an additional role, which typically requires 300–500 personnel to perform.⁵¹ The combatant command as joint force land component command option also requires one subordinate corps to “dual-hat” as the ARFOR within the joint operations area.⁵² Therefore, this option actually increases administrative and coordination requirements for the corps rather than relieving them.

Another option would be co-opting existing force structure. However, this would be ineffective because of political constraints. In Korea, the U.S. maintains the Eighth Army, which is technically a field army. However, it has a reduced staff structure and focus based on treaty obligations from the Korean War.⁵³ Additionally, national-level political leadership’s authority is required to withdraw from the numerous bilateral agreements concerning our combined security framework with South Korea.⁵⁴ This means that the Eighth Army cannot be easily or rapidly pulled off the peninsula to perform a field army mission elsewhere in the world and it must be backfilled. As for NATO’s Multi-Corps Land Component Command, it depends on the U.S. Army Europe and Africa staff to form it.⁵⁵ This then encounters the same challenges noted with using the theater army as a field army headquarters. Additionally, as a NATO construct, the Multi-Corps Land Component Command is heavily constrained by the politics and national caveats associated with contributing nations, thereby limiting its responsiveness and freedom of action.

A final alternative is to create an ad hoc field army during conflict. However, a field army headquarters created during conflict is not effective because it would be late to need (see figure 7). During World War II, it took one to three months from the time a field army was established until it could begin planning and preparation.⁵⁶ Then the planning and preparation time averaged three to five months.⁵⁷ This means that historically it takes four to eight months to establish a fully functional field army—a long time for the joint force commander to wait for the Army to be fully ready.

Timeliness can be decisive too. By the time an ad hoc field army can be assembled and fielded, it may be too late to prevent significant loss of territory. For example, Eighth Army, performing occupation duties in Japan, immediately responded to the North Korean invasion of South Korea in 1950. In command of an ad hoc multinational force, Eighth Army proved instrumental in slowing the North Korean advance and ultimately preserving the Pusan Perimeter and the United States’ foothold on the peninsula.⁵⁸ It is possible that without an immediately available field army, the United States would have been forced to abandon the Korean Peninsula.

Field Army Structure

The final question to address is the cost for a field army. A service-retained field army headquarters should be relatively small and designed to be tactically focused. The total size should be between 250 and 400 soldiers (smaller being better) with a three- or four-star commander. This is much less than the 1,069 authorized personnel in the 1944 field army table of organization and equipment but consistent with operational employment by some World War II field armies, like Fifth Army.⁵⁹ Modern analysis supports the recommended number too. U.S. Army Europe and Africa recently assessed its requirements to act as a multi-corps land component command in Europe and found it needed approximately 400–500 personnel for that role.⁶⁰ As the Army Ground Forces stated during headquarters consolidations in July 1943, “[Staffs] are to be provided solely for combat needs. Operations cannot possibly be swift and effective if staffs are large and clumsy.”⁶¹ The same principle applies in this proposal, which means wherever possible, administrative and support tasks should be pushed to the theater army.

A field army should only have a headquarters and headquarters battalion as its organic force structure. The headquarters is the core of the proposal, while the headquarters battalion provides administrative and logistics support for the headquarters and all organic command post elements. In my proposal, the field army is then assigned whichever corps are employed in the conflict. For example, in a conflict in Europe, the proposed field army would deploy to the European Command area of responsibility, be assigned to the joint force commander, and then have V Corps and III Corps assigned to it. This modular approach is the same as used by Army Ground Forces during World War II with corps and armies, enabling flexible employment and the ability to rapidly change task-organization to meet dynamic requirements.⁶²

The field army would require a main command post and a tactical command post. A main command post “is a portion of a unit’s headquarters containing the majority of the staff designed to command and control current operations, conduct detailed analysis, and plan future operations.”⁶³ The main command post requirement is obvious; meanwhile, the tactical command post is “designed to command and control operations as directed.”⁶⁴ Today’s field armies could use their tactical command posts similar to World War II, such as during large-scale joint forcible entry operations like Fifth Army at Salerno and Anzio, during split operations like First Army’s reduction of the Ruhr Pocket, or during large-scale complex operations like Fifth Army’s army-wide crossing of the Volturno River.⁶⁵ These command posts should be mobile, dispersible, and able to organically communicate on joint and Army networks.

The staff structure would resemble other echelons above brigade headquarters and headquarters battalion and use a general staff (G). During World War II, general officers were typically located in field armies in the command group and as the directors for the G-3 (assistant chief of staff, operations) and G-4 (assistant chief of staff, logistics). Colonels mostly led the other directorates.⁶⁶ A similar grade-plate distribution for directors would be generally consistent with current theater armies and corps, except the G-4s who are currently colonels.

As part of minimizing the grade plate, the Army can use subordinate formations to augment the field army staff. This approach replicates Army Ground Forces Command army design during World War II.⁶⁷ In conflict, the Army can assign a general officer-led sustainment organization, like an expeditionary sustainment command, to a field army that would assist the field army commander with general officer oversight of sustainment.⁶⁸ This would mitigate some of the risk associated with having an O-6 rather than a general officer as the field army G-4. The same goes for the fire support coordinator. For example, the Army can assign a general officer-led fires formation like an Operational Fires Command to a field army in conflict. The fires formation would provide general officer oversight to fires, could be used to employ the multi-domain task force, and act as the field army’s fire support coordinator. Like with the G-4, this mitigates the risk of having an O-6 fire support coordinator in the field army. Using subordinate formations to augment the field army also allows the Army to minimize grade-plate and total spaces in the field army headquarters as the field army could then delegate specific planning responsibilities to the subordinate augmentation command.

Conclusion

The Army needs to invest in a field army headquarters to be prepared for large-scale combat operations. It will be challenging in the current political environment, where “no growth” has become the mantra for any Army force structure adjustment. Further study is necessary to determine the exact staff requirements by the military occupational specialty and grade to fill a field army headquarters and then to identify appropriate billpayers. One method would be to adopt the development of a field army headquarters as a program objective memorandum (known as POM) planning task to force institutional mechanisms to perform the analysis. Another method is to adopt it into the Army’s warfighting concept as part of the future Army. Regardless, with a field army headquarters, the Army will be better prepared to maximize the lethality of its corps in large-scale combat operations—and our adversaries will know it too.

 

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Notes

1. Field Manual (FM) 3-0, Operations (U.S. Government Publishing Office [GPO], 2022), 2-19.
2. Alex Vershinin, “Feeding the Bear: A Closer Look at Russian Army Logistics and the Fait Accompli,” War on the Rocks, 23 November 2021, https://warontherocks.com/2021/11/feeding-the-bear-a-closer-look-at-russian-army-logistics/.
3. David A. Shlapak et al., Reinforcing Deterrence on NATO’s Eastern Flank: Wargaming the Defense of the Baltics (RAND Corporation, 29 January 2016), https://www.rand.org/pubs/research_reports/RR1253.html; Richard D. Hooker Jr., “A New NATO Command Structure,” Atlantic Council, 5 June 2024, https://www.atlanticcouncil.org/in-depth-research-reports/issue-brief/a-new-nato-command-structure/.
4. James Rainey and Laura Potter, “Delivering the Army of 2030,” War on the Rocks, 6 August 2023, https://warontherocks.com/2023/08/delivering-the-army-of-2030/.
5. Emma Chanlett-Avery et al., The North Korean Challenge: Military Options and Issues for Congress (Congressional Research Service [CRS], 6 November, 2017), https://crsreports.congress.gov/product/pdf/R/R44994; Allan R. Millett, “Invasion and Counterinvasion, 1950-1951,” in Encyclopedia Britannica, updated 26 August 2025, https://www.britannica.com/event/Korean-War/Invasion-and-counterinvasion-1950-51; Kenneth Katzman et al., U.S.-Iran Conflict and Implications for U.S. Policy (CRS, 8 May 2020), https://crsreports.congress.gov/product/pdf/R/R45795.
6. William E. Rapp, “Civil-Military Relations: The Role of Military Leaders in Strategy Making,” Parameters 45, no. 3 (September 2015): 13–26, https://press.armywarcollege.edu/parameters/vol45/iss3/4/.
7. “Large-Scale Ground Combat Operations Study,” PowerPoint presentation, U.S. Army Training and Doctrine Command (TRADOC), 2019, https://armyeitaas.sharepoint-mil.us/:p:/r/sites/TR-CAC-CACT-MCTP-OGB/_layouts/15/Doc.aspx?sourcedoc=%7B28D9BCA4-D41A-4B7C-A4A8-61D5B65A2C9B%7D&file=LSCO%20Gap%20Study%20V5).pptx&action=edit&mobileredirect=true&DefaultItemOpen=1.
8. Thomas C. Schelling, Arms and Influence (Yale University Press, 1966), 3–4.
9. FM 3-0, Operations, 2-17.
10. FM 3-0, Operations, 2-17.
11. FM 3-0, Operations, 6-1.
12. Joint Publication (JP) 3-31, Joint Land Operations (U.S. GPO, 3 October 2019, incorporating Change 2, 31 March 2023), II-10.
13. Army Techniques Publication (ATP) 3-92, Corps Operations (U.S. GPO, 2016), I-2.
14. V Corps, https://www.vcorps.army.mil/About-Us/Mission-History/, is dedicated to Europe; and I Corps, https://www.army.mil/ICorps#org-about, is dedicated to the Indo-Pacific.
15. Roger Wicker, 21st Century Peace Through Strength: A Generational Investment in the U.S. Military (U.S. Senate, 2025), https://www.wicker.senate.gov/services/files/BC957888-0A93-432F-A49E-6202768A9CE0.
16. V Corps in Europe, I Corps in the Indo-Pacific, and XVIII and III Corps are the tactical corps in the conflict.
17. Thomas Haydock et al., “Lessons in Reconstitution from the Russia-Ukraine War: Gaining Asymmetric Advantage Through Transformative Reconstitution,” Military Review 105, no. 5 (January-February 2025): 26–41, https://www.armyupress.army.mil/Portals/7/military-review/Archives/English/January-February-2025/Lessons-in-Reconstitution/Lessons-in-Reconstitution-UA.pdf.
18. TRADOC Pamphlet 525-92, The Operational Environment 2024–2034 (TRADOC, December 2024), https://rdl.train.army.mil/catalog-ws/view/100.ATSC/26EDC9BD-A6C6-4BD8-B663-88DB4528F896-1734185694520/TP525-92_Final.pdf.
19. JP 3-31, Joint Land Operations, II-10.
20. John Bonin, “Echelons Above Reality: Armies, Army Groups, and Theater Armies/Army Service Component Commands (ASCCs),” in Essential to Success: Historical Case Studies in the Art of Command at Echelons Above Brigade, ed. Kelvin Crow and Joe R. Bailey (Army University Press, 2017), 259.
21. FM 3-93, Theater Army Operations (U.S. Government Printing Office, 2011), 3-1; To Conduct a Confirmation Hearing on the Expected Nomination of Mr. Peter B. Hegseth to be Secretary of Defense, 119th Cong. (14 January 2025), 2:40:43, https://www.rev.com/transcripts/pete-hegseth-senate-confirmation-hearing.
22. ATP 3-93, Theater Army Operations (U.S. GPO, 2021), 1-1.
23. ATP 3-93, Theater Army Operations, 1-2.
24. Report of the General Board, United States Forces, European Theater, “Organization of the European Theater of Operations,” app. 23 in Study of the Organization of the European Theater of Operations, Study Number 2 (General Board, 1943), 2–3, https://carlcgsc.libguides.com/ld.php?content_id=52563394.
25. Report of the General Board, United States Forces, European Theater, “HQ ETO USA,” chap. 1 in Organization and Functions of the Communications Zone, Study Number 127 (General Board, 12 February 1945), app. 8–43, https://carlcgsc.libguides.com/ld.php?content_id=52621666. The Communications Zone staff number approximately 10,650: 11 (Command Group), 93 (G-1), 136 (G-2), 168 (G-3), 221 (G-4), 86 (G-5), 73 (Judge Advocate), 220 (Adjutant General), 98 (Chemical), 712 (Quartermaster), 1,666 (Signal), 372 (Surgeon), 1,000 (Transportation–SWAG), 505 (Engineer), 919 (Ordnance), 123 (Provost Marshal), 32 (Inspector General), 15 (Antiaircraft), 11 (Artillery), 10 (Armored), 119 (General Purchasing), 46 (Public Relations), 50 (Claims), 98 (Army Exchange), 13 (Military Labor), 10 (Redeployment), 43 (Historian), 422 (G-8), 2,170 (Headquarters Command), 770 (Special and Information Services), 15 (Chaplain), 400 (Ground Force Reinforcement Command), 7 (Air), and 16 (Liaison). This number EXCLUDES the section commands, which were the operational arm of the Communication Zone (like the Theater Sustainment Command is to the modern theater army). This supported three Allied army groups that combined for approximately three million personnel. That ratio is 1:282 (Communication Zone:Soldier).
26. The assumption is that two fully enabled corps and a field army with its enablers equate to approximately one hundred thousand soldiers.
27. Kevin C. Benson, Expectation of Valor: Planning for the Iraq War (Casemate Publishers, 2024), 36–47.
28. Eric S. Edelman et al., “NATO’s Decision Process Has an Achille’s Heel,” New Atlanticist (blog), Atlantic Council, 12 March 2024, https://www.atlanticcouncil.org/blogs/new-atlanticist/natos-decision-process-has-an-achilles-heel/; NATO Allied Command Transformation, “Joint Force Development Experimentation & Wargaming Branch Fact Sheet – Multi Corps Land Component Command Concept (MC LCC),” NATO, accessed 8 September 2025, https://www.act.nato.int/wp-content/uploads/2023/05/EWB_Fact_Sheets_2022_EX_Multi_Corps_Land_Component_Command_Concept.pdf; Gareth Jones, “NATO to Setup Northern Land Command in Eastern Finland,” Reuters, 27 September 2024, https://www.reuters.com/world/europe/nato-set-up-northern-land-command-eastern-finland-2024-09-27/; “NATO Multi-Corps Land Component Command (MCLCC) in the North Fosters Defence Planning of the Alliance,” Finnish Defence Forces, 27 September 2024, https://puolustusvoimat.fi/en/-/nato-multi-corps-land-component-command-mclcc-in-the-north-fosters-defence-planning-of-the-alliance.
29. Yama Sakura 87 Combined Joint Information Bureau, “Trilateral Iteration of Yama Sakura, Concurrent Warfighter Exercise to Launch in Japan,” U.S. Army, 5 December 2024, https://www.army.mil/article/281784/trilateral_iteration_of_yama_sakura_concurrent_warfighter_exercise_to_launch_in_japan.
30. U.S. Army Europe and Africa, “US, NATO Allies and Partners to participate in Exercise Avenger Triad 24,” press release, 5 September 2024, https://www.europeafrica.army.mil/ArticleViewPressRelease/Article/3892335/press-release-us-nato-allies-and-partners-to-participate-in-exercise-avenger-tr/.
31. Terry Welch, “USAREUR-AF Leads Forum on NATO Convergence at AUSA,” U.S. Army, 16 October 2024, https://www.army.mil/article/280539/usareur_af_leads_forum_on_nato_convergence_at_ausa.
32. 10 U.S.C. § 7013 (2018).
33. 10 U.S.C. § 7013(b). The secretary of the Army is assigned twelve responsibilities, ten of which are delegated to the theater-level: organizing; supplying; equipping; training; servicing; mobilizing; demobilizing; administering (including the Uniform Code of Military Justice); outfitting and repairing military equipment; and acquisition of real property and construction, maintenance, and repair of buildings.
34. JP 1, The Joint Force, vol. 2 (U.S. GPO, 2020), GL-4.
35. FM 3-94, Armies, Corps, and Division Operations (U.S. GPO, 2021), 1-14.
36. FM 3-94, Armies, Corps, and Division Operations, B-2.
37. Department of the Army Deputy Chief of Staff for Operations, memorandum, “The Concept for the 1970-1980 Field Army, Army 80,” United States Army Combat Developments Command, drafted August 1963, 7.
38. Benson, Expectation of Valor, 85.
39. FM 3-0, Operations, fig. 6-2.
40. Seventh U.S. Army, Seventh Army History, Part Two, Chapters XXVII thru XXXI, Phase Four (Seventh U.S. Army, n.d.), 1187, https://cdm16040.contentdm.oclc.org/digital/collection/p4013coll8/id/4739/rec/1.
41. First U.S. Army, Report of Operations, 23 February – 8 May 1945, vol. 1 (U.S. Government Printing Office, 1946), 77, https://cplorg.contentdm.oclc.org/digital/collection/p16014coll14/id/1883.
42. Center for Army Lessons Learned (CALL), FY 23 Mission Command Training in Large-Scale Combat Operations Key Observations (CALL, 2024), 8–11, https://www.army.mil/article/274300/fy_23_mission_command_training_in_large_scale_combat_operation_key_observations.
43. Milford Beagle et al., “The Graveyard of Command Posts: What Chornobaivka Should Teach Us About Command and Control in Large-Scale Combat Operations,” Military Review Online Exclusive (28 March 2023), 14, https://www.armyupress.army.mil/journals/military-review/online-exclusive/2023-ole/the-graveyard-of-command-posts/.
44. Kent Roberts Greenfield et al., The Army Ground Forces: The Organization of Ground Combat Troops, United States Army in World War II (1947; repr., Center of Military History, 1987), 291, https://history.army.mil/portals/143/Images/Publications/catalog/2-1.pdf.
45. Greenfield et al., Organization of Ground Combat Troops, 291.
46. “Beginning a New Era,” U.S. Army, 4 October 2024, https://home.army.mil/drum/about/news/news-archives-october-2024/beginning-new-era.
47. First U.S. Army, Report of Operations, 23 February – 8 May 1945, vol. 2 (U.S. Government Printing Office, 1946), 106.
48. Robert Palmer, Reorganization of Ground Troops for Combat, Army Ground Forces Study No. 8 (Historical Section, Army Ground Forces, 1946), 76, https://cgsc.contentdm.oclc.org/digital/collection/p4013coll8/id/4497/; First U.S. Army, Report of Operations, 1:94.
49. Per Army doctrine, especially ATP 3-92, Corps Operations, the preferred joint task force headquarters (HQ) is the corps. However, as already discussed, in this scenario there is not an available corps HQ. Theater armies can also perform the joint task force HQ role, but they are also not available because of their Army Service component command responsibilities. Finally, divisions can perform the joint task force HQ role, but they are least equipped and not ideal (grade-plate wise) for being a large-scale combat operations joint task force HQ, especially for a multi-corps fight.
50. 10 U.S.C. § 164 (2018). As an example, Gen. Christopher G. Cavoli’s posture statement on the U.S. European Command to the U.S. House Armed Services Committee lists many of the ongoing activities in Europe. See U.S. Military Posture and National Security Challenges in Europe Before the House Armed Services Committee, 118th Cong. (10 April 2024) (statement of Gen. Christopher G. Cavoli, U.S. European Command), https://armedservices.house.gov/sites/evo-subsites/republicans-armedservices.house.gov/files/USEUCOM%20GEN%20Cavoli%20CPS_HASC_2024.pdf.
51. Chad Pillai (colonel, U.S. Army Europe and Africa G-5 chief of plans), email message to author, 25 March 2025; ATP 3-92, Corps Operations (U.S. GPO, 2016), 4-1.
52. FM 3-94, Armies, Corps, and Division Operations (U.S. GPO, 2021), B-1.
53. FM 3-94, Armies, Corps, and Division Operations, 3-23.
54. Timothy Olliges, (major, chief of Eighth Army National Security Law), email message to author, 10 September 2025.
55. Welch, “NATO Convergence.”
56. Clark, Calculated Risks, 145. Fifth Army stood up in approximately one month. “Mark. W. Clark Diary, December 2, 1942 – January 5, 1943,” The Citadel Archives Digital, 159, accessed 9 September 2025, https://citadeldigitalarchives.omeka.net/items/show/806. However, most of its staff came from II Corps, so that essentially represents the option of using a separate corps HQ. Third U.S. Army, After Action Report, 1 August 1944–9 May 1945, vol. 1, The Operations (Third U.S. Army, 1945), 1, https://cdm16040.contentdm.oclc.org/digital/collection/p4013coll8/id/2199/rec/1. Third Army HQ, which already existed, required three months to prepare and deploy from the United States to England. Leonard T. Gerow, History of the Fifteenth United States Army, 21 August 1944 to 11 July 1945 (Fifteenth U.S. Army, 1945), 6–10, https://cdm16040.contentdm.oclc.org/digital/collection/p4013coll8/id/2977/rec/1. Fifteenth Army, which was formed from the existing Fourth Army, took approximately two and a half months to prepare and deploy from the United States to Scotland. Sixth U.S. Army, Report of the Leyte Operation, 20 October 1944 to 25 December 1944 (Sixth U.S. Army, 1944), 1–2, https://cdm16040.contentdm.oclc.org/digital/collection/p4013coll8/id/3168/rec/1. Sixth Army was constituted and then began operations in Australia in approximately one month.
57. Fifth U.S. Army, Fifth Army History, vol. 1, From Activation to the Fall of Naples, 5 January – 6 October 1943 (U.S. Government Printing Office, 1945), 13, https://cgsc.contentdm.oclc.org/digital/collection/p4013coll8/id/1451. At the high end, Fifth Army spent over eight months planning and preparing for an invasion of Sicily or Italy, although they had to wait for the defeat of German forces in North Africa before proceeding, which added time. Third U.S. Army, After Action Report, 1. Third Army spent approximately three and a half months planning for Operation Overlord. Seventh U.S. Army, Seventh Army History, Invasion Southern France, Phase One (Seventh U.S. Army, n.d.), 1–2, https://cdm16040.contentdm.oclc.org/digital/collection/p4013coll8/id/5725/rec/3. Seventh Army spent five months planning and preparing for the initial planned date for Operation Anvil and the invasion of southern France. Sixth U.S. Army, Report of the Leyte Operation, 17. Sixth Army’s planning and preparation for the Leyte invasion took approximately three months. Gerow, History of the Fifteenth United States Army, 10–15. Fifteenth Army began operations in France after approximately two months planning and preparation in Scotland.
58. Walter T. Ham IV, “Eighth Army Honors Pusan Perimeter Defenders,” U.S. Army, 17 September 2013, https://www.army.mil/article/111382/Eighth_Army_honors_Pusan_Perimeter_defenders/.
59. Report of the General Board, United States Forces, European Theater, Report on the Organization of the Army Headquarters and Headquarters Company, Study Number 24 (General Board, 1943), 1–2, https://carlcgsc.libguides.com/ld.php?content_id=52565934; “Mark W. Clark Diary, January 6, 1943 – February 25, 1943,” 5, The Citadel Archives Digital Collections, accessed 9 September 2025, https://citadeldigitalarchives.omeka.net/items/show/825.
60. Pillai, email message.
61. Palmer, Reorganization of Ground Troops for Combat, 82.
62. Greenfield et al., Organization of Ground Combat Troops, 363.
63. FM 6-0, Commander and Staff Organization and Operations (U.S. GPO, 2022), 7-5.
64. FM 6-0, Commander and Staff Organization and Operations, 7-6.
65. Fifth U.S. Army, “Field Order No. 4, 19 September 1943,” in Fifth Army History, 1:87; Clark, Calculated Risks, 296; First U.S. Army, Report of Operations, 2:76–77; Fifth U.S. Army, Fifth Army History, vol. 2, Across the Volturno to the Winter Line, 7 October – 15 November 1943 (U.S. Government Printing Office, 1945), 15–16, https://cgsc.contentdm.oclc.org/digital/collection/p4013coll8/id/1410.
66. First U.S. Army, Report of Operations, 1:iii–xv. As an example, First Army in 1944 was organized with a command group, G-1, G-2, G-3, G-4, G-5, adjutant general, anti-aircraft section, propaganda and psychological warfare section, artillery section, chaplain, chemical warfare section, engineers, special troops headquarters, inspector general, ordnance section, armored section, finance section, headquarters command section, judge advocate general, medical section, provost marshal, quartermaster section, signal section, and special service section.
67. Greenfield et al., Organization of Ground Combat Troops, 260.
68. This is similar to how the Army approaches current theater armies, which have theater sustainment commands, and corps, which have corps sustainment commands.

 

 

 

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November-December 2025