We Need Joint Marine Corps–Army Constructive Exercises

In June 1918, near France’s Belleau Wood, the U.S. Army and Marine Corps were sent into action in a desperate attempt to stop a German breakthrough that threatened Paris. The 2nd Infantry Division, reinforced with the Marine Corps’ 4th Brigade, moved forward through shattered French Army forces who were falling back in disarray from the attacks of at least five German divisions. Assessing the situation, Army and Marine Corps leaders determined a defensive scheme, seized key terrain, and established hasty positions from which to fight. Over the following two weeks, the U.S. forces defeated successive German assaults that employed everything from attempted night infiltrations to large quantities of chemical weapons. Having blunted the German offensive, U.S. forces reconsolidated and then, in a determined and bloody counterattack, cleared Belleau Wood of German forces and paved the way for further Allied offensive operations.¹ 

Those events are salient to today’s Marine Corps for two reasons. First, Belleau Wood instilled in the Marine Corps an esprit de corps and martial lore that endures to this day. Second, they established a tradition of Marine Corps–Army cooperation at the tactical and operational level from which both services would draw for the remainder of the 20th century and into the 21st. In locales as disparate as Peleliu, Okinawa, Korea, Vietnam, and Kuwait, the Army and Marine Corps have conducted mutually supportive operations in support of national objectives. In all cases, the two services’ unique capabilities provided operational and theater commanders the ability to present diverse and insurmountable problems to the nation’s enemies to achieve operational success. 

Unfortunately, almost two decades of recent counterinsurgency (COIN) warfare have atrophied many of the cooperative skills necessary for Army–Marine Corps success in large-scale combat operations (LSCO). At the tactical level, common equipment, compatible small-unit doctrine, and similar individual and collective tasks will go far to facilitating coordination. As demonstrated at the Battle of Fallujah in November 2004, Army and Marine Corps tactical formations, from platoons to the brigade/regimental combat team level, can function well together. Provided small units are fully trained and well-led, company and field grade officers liely will “figure things out” against a peer or near-peer opponent despite the myriad of differences between COIN and LSCO.² 

The training that underpins this tactical expertise and compatibility is absent at the operational level, however. This gap is not lacking in doctrine, as Joint Publication (JP) 3-31, Joint Land Operations, lays out the theoretical foundation for joint or combined land component commander operations from the operational- to theater-levels of war.³ Instead, training shortcomings arise from the fact that Army corps/divisions and Marine air ground task force (MAGTF) headquarters have not conducted an interservice joint exercise in at least 20 years.⁴ Despite sister-service response cells at Army Mission Command Training Program (MCTP) Warfighter Exercises/MAGTF Staff Training Program (MSTP) training events, the majority of Army and Marine Corps staffs have not been exposed to how their counterparts would operate in large-scale combat. Nor have recent exercises compelled Army or Marine Corps senior commanders to interact and collectively train how they are going to operate against a common opponent in such a scenario.

This lack of collective staff training needs to be remedied. In a high-end fight, the nation’s land-combat services will face a single foe whose chain of command will be operating off a prepared, rehearsed war plan. In contrast, as presently trained, Army and Marine Corps senior leaders and staffs would have to determine procedures on the fly while discovering friction points under operational pressure. With recent wargames at the Marine Corps War College forecasting casualties in the tens of thousands, the nation cannot afford this level of disorganization. Therefore, the Army and Marines Corps should cooperatively develop an operational headquarters constructive exercise (call it the “Belleau Spirit”) to prepare senior leaders and staffs for major conflicts against peer opponents. 

Marine Corps and Army Roles in Large-Scale Combat Operations

As the primary land-warfare component, the Army is responsible to “[c]onduct prompt and sustained combat incident to operations on land.”⁵ The Marine Corps is tasked with “the seizure or defense of advanced naval bases and for the conduct of such land operations as may be essential to the prosecution of a naval campaign.”⁶ These responsibilities are further clarified in Department of Defense (DoD) Directive 5100.01, Functions of the of the Department of Defense and Its Major Components, with the Marine Corps’ responsibilities expanded to also include “complex expeditionary operations in the urban littorals and other challenging environments.”

The DoD has publicly espoused the “challenging environments” that might be encountered in future conflicts. The 2018 National Defense Strategy highlighted northeastern Europe, the Korean peninsula, and the Persian Gulf region as the three most likely areas where the United States military would face a major conflict. Land combat in each region would almost certainly involve multiple divisions and/or corps headquarters operating under a joint or combined land component commander. Further examination of all three regions shows major cities, lines of communication, and critical facilities along likely axes of advance and well within the littoral combat zone. These factors all make it hard to see a scenario where Army divisions/corps, MAGTFs, and multinational partners are not all operating in adjacent areas toward a common operational goal. 

Train As You Fight

The need for operational training should be readily apparent in lieu of likely employment. Indeed, as mentioned, both the Army MCTP and Marine Corps MSTP maintain organizations solely designed to train division, corps, and MAGTF staffs in operational maneuver in accordance with each service’s operational doctrine. In the case of the Army, Army Forces Command (ForsCom), supported by Training and Doctrine Command (TraDoc), directs MCTP to hold at least one annual corps- and multiple division-level exercises in support of expected operational requirements. For the Marine Corps, the MSTP provides training to Pacific- and Atlantic-based MAGTF, Marine expeditionary battalion (MEB), and division staffs as required in support of designated fleet operations. 

With MCTP and MSTP regularly exercising their respective headquarters, intraservice training is not an issue. What is urgently needed, especially in light of growing threats and the National Defense Strategy, is a joint training program that builds on this training by forcing selected headquarters to operate as they would be expected to fight in a major land conflict. In addition to ensuring flag officer command staffs are familiar with the distinctive Army and Marine Corps capabilities, these exercises would also allow combatant commanders an opportunity to review and revise their operational planning. Put another way, Belleau Spirit exercises would permit European, Indo-Pacific, and Central commands to ensure plans conceived in Phase 0 of joint operations would actually be feasible in successive phases, should conflict occur.

Stealing a March

Much like the months of training before Belleau Wood allowed the U.S. forces to fight with great effectiveness, establishing Belleau Spirit exercises will help MAGTFs, division, and corps staffs to steal a march on the initial chaos of future large-scale operations. For Army leaders and staffs, this will be reflected in increased knowledge of the Marine Corps’ ability to achieve operational objectives and threaten an opponent’s flank “from the sea.” For Marines, Belleau Spirits will create opportunities to better understand a possible JTF headquarters’ scheme of maneuver and therefore where a MAGTF can best impose its will on hostile forces. For both services’ senior leaders, established procedures and an understanding of Army and Marine Corps capabilities will allow them to meet potential opponents on even operational footing. This, in turn, means soldiers and Marines will pay for lessons in sweat rather than blood should conflict arise. For all these reasons, the time to begin planning the first Belleau Spirit exercise involving a MAGTF and corps/division headquarters is now.