The principal role of the Army's sustainment warfighting function is well established in doctrine. It is to provide support and services to "ensure freedom of action, extend operational reach, and prolong endurance." The implication is as clear as it is true; without such support, the warfighter cannot effectively generate and apply his full combat potential when decisively engaged with the enemy. The complexity of warfare during large-scale combat operations (LSCO) will increase significantly beyond that of the counterinsurgency fight, and the importance of sustainment operations to success will likewise increase.THE DISTRIBUTION CHALLENGESustaining the battlefield during LSCO will be an extraordinary challenge, especially given the complexity of Multi-Domain Operations (MDO) against a peer competitor. A depot-based supply system with "iron mountains" of supplies will not work in the next fight. We must focus instead on improving our ability to accurately forecast and precisely deliver what the warfighter needs during high-volume, high-intensity operations.The increased demands of simultaneous, geographically dispersed operations require more sophisticated planning and coordination to account for rapidly advancing units within a highly contested environment. In order to achieve precision and responsiveness, all sustainment elements must be inextricably integrated and synchronized early in the planning process and throughout operations.The sustainment plan cannot merely be consulted by maneuver units just before execution. The plan must be synchronized in time and space to achieve the effects required by the warfighter at echelon. The distribution challenge during LSCO is less about supply availability and more about the availability of transportation assets to deliver a high volume of supplies with precision to the right unit at the right time and at the right location.Following the invasion of Normandy in 1944, the Third Army advanced eastward across France in pursuit of German forces while facing intense force-on-force combat operations. To maintain the pursuit, the Third Army's fuel demand was an average of more than 350,000 gallons a day.To sustain the Allied advance, the Army consolidated trucks from various units, including infantry battalions, to form a 6,000 vehicle fleet famously known as the Red Ball Express. Despite the Red Ball Express efforts, Patton's Army was immobilized for nearly two months, unable to extend its operational reach during a time of relative advantage. This immobilization was due to inefficiencies and deficiencies in the supply chain, which created a cascading effect within the Third Army, causing shortages of ammunition, clothing, rations, and other key commodities as winter was approaching.To put the Third Army's fuel consumption in perspective, 350,000 gallons of fuel a day will support three modern armored brigade combat teams--the maneuver arm of one heavy division--during high-intensity LSCO. This does not include enough fuel for aviation or other units in the division support area and the division consolidation area, let alone an entire field army with multiple corps.This example highlights that today's Army requires a robust distribution network with distribution assets that support precision delivery of a vast amount of materiel and equipment on the battlefield. Simply put, we cannot win with inaccurate forecasting, inefficient distribution, or simple plans.The scale and scope of LSCO present significant challenges to our distribution networks, particularly when establishing continuous, rapid resupply to the forward line of troops and beyond. Many variables affect our ability to achieve precision and speed in sustaining the warfighter. Some of these challenges include reduced operational readiness of sustainment platforms, unpredictable turnaround times at points of delivery, stressed and targeted communications networks, combat attrition, combat loss, sabotage to key transportation infrastructure, congestion within our lines of communication, dispersion of units causing longer lines of communication, and increased security requirements to defend dispersed base clusters. None of these are simple problems for sustainers to solve.IS SIMPLICITY STILL A PRINCIPLE OF SUSTAINMENT?The difference between victory and defeat on the battlefield largely depends on the Army's ability to marshal, transport, and distribute large quantities of supplies while maintaining the forward momentum of personnel and equipment. This is achieved through continuous integration and synchronization of sustainment activities in support of the unit commander at echelon.Our sustainers must operate as a unified team, from the strategic support area in the continental United States through the joint security area to the foxhole. This involves meticulous coordination to ensure resources are delivered to the point of need. Operating within functional stovepipes will render formations vulnerable to enemy interdiction while suboptimizing the ability to deliver critical supplies to the warfighter on time and on target.Orchestrating all the diverse sustainment activities is complex in nature. The sustainment infrastructure on the battlefield during LSCO will be multifaceted, consisting of multiple nodes, modes, and routes as well as redundant communications that provide our adversaries with multiple dilemmas to solve across the sustainment warfighting function. Leveraging all aspects of sustainment to ensure that there is no single point of failure that prevents the delivery of critical supplies and services to the warfighter is critical to this effort. These aspects include the effective use of air, land, sea, inland waterways, and autonomous air and ground platforms where feasible.In the air, sustainment operations will include fixed and rotary-wing aircraft providing air evacuation and air-land, airdrop, sling-load, and precision-guided deliveries of supplies and equipment. Delivery using air assets will be the norm rather than the exception. On land we will use multiple roads, rail networks, and pipelines to deliver goods and services to the point of need. We will also use watercraft to deliver supplies and equipment by way of seaports, rivers, canals, and off-the-shore opportunities. Included in our sustainment planning will be deception plans that are integrated at the operational and tactical levels.The LSCO operating environment is highly dynamic and consists of multiple formations with unforeseeable interdependencies that emerge simultaneously across multiple domains. Inherently, this type of sustainment problem set will be complex; however, complexity within the sustainment warfighting function should not have a negative connotation.Simplicity as a principle of the sustainment warfighting function may be difficult to achieve on the modern battlefield--especially if sustainment is not fully integrated in the appropriate mission command systems. It is important that we integrate our sustainment operations with other warfighting functions and ensure our staff design and staff processes are fully immersed with the warfighter.We must exploit technologies such as artificial intelligence, enterprise resource planning systems, and available prognostic analytical tools to enable accurate demand forecasting and achieve better responsiveness. While we will strive to build simplicity into our processes and procedures where it can be achieved, we cannot underestimate the complexity of the modern battlefield and the corresponding sustainment system that it will demand.SECURITY DURING LSCODuring counterinsurgency operations in Iraq and Afghanistan, coalition forces have enjoyed dominance across all domains with minimal threat of enemy activity overrunning critical logistics nodes. The joint operations area had a green zone with fixed and fortified forward operating bases and combat outposts where security was often outsourced or enhanced by contracted personnel or host-nation support.In LSCO, security will not be outsourced and sustainment units will require security plans that account for operations that Field Manual 3-0, Operations, describes as "more chaotic, intense, and highly destructive than those the Army has experienced in several decades." Our units must be trained and proficient at defending their assigned areas. First and foremost, sustainment units will be responsible for their security. There will be no green zones; all domains will be contested. Both supporting and supported leaders must fully appreciate and understand the security measures required to secure logistics nodes and various lines of communications during LSCO.The support area command post at echelon will play a central role in coordinating and synchronizing security assets to clear and secure key logistics nodes. These operations include prioritizing fires, route clearance, close-air support, and intelligence, surveillance, and reconnaissance. We must deliberately coordinate and communicate those sustainment security requirements on the battlefield.WE MUST EDUCATE AND TRAIN TO WINThough technology will help us deal with complexity, we cannot ignore the human dimension of MDO. The sustainment community's education and training approach must evolve to account for the scale, tempo, and rigor required to prevail in LSCO. Leaders in both the operational and institutional realms cannot allow units to run back to garrison dining facilities, supply support activities, or fuel and water points during field training exercises. The environment in which we train must be realistic and present the challenges that units and leaders will face during LSCO. This realism is critical to having trained and proficient combat-ready units.Leveraging live and virtual training tools, individually and collectively through the institutional, operational, and self-development domains, is key to enabling leaders and units to gain proficiencies in sustaining the complex battlefield. Leaders in the operational force and faculties in the institutions must stay relevant by understanding how sustainment will be conducted in MDO and what training tools and techniques are available to prepare Soldiers for these operations.We need to create conditions to force both sustainment and maneuver leaders to think through the scale and scope of the distribution challenge. Whether at a combat training center, during a warfighter exercise, or at home station using the Synthetic Training Environment, we must replicate the full complexity of the operational environment with practical problem sets that allow our units and leaders the necessary repetitions to achieve proficiency. This includes fully integrating with the warfighter's tactical networks, mission command information systems (fully functioning and degraded), and staff processes at echelon during training exercises.Self-development is a critical component of effecting this change. Every lower enlisted Soldier, noncommissioned officer, and officer should find ways to enhance their professional competence. They need to track lessons learned from combat training centers, maintain relationships with their peers in the operational and institutional force, and read and reflect on modern warfare and sustainment. Sustainment leaders must understand and discuss maneuver warfare and ensure maneuver leaders understand how best to leverage sustainment capabilities across the battlefield. They cannot simply expect their leadership to hand them opportunities. All Army professionals are responsible for their own development.War today and in the future is a complex business. The operational environment that we are planning to fight in is vastly different than what we have experienced over the past 18 years, but our principal responsibility to the warfighter remains the same. The sustainment warfighting function will provide support and services to ensure freedom of action, extend operational reach, and prolong endurance so that our Army can prevail during LSCO. This requires detailed planning across the sustainment warfighting function and complete integration and synchronization with the warfighter at echelon.Our sustainment system must be comprehensive with no singular points of failure to ensure we achieve the required effects at the speed, volume, and lethality required for LSCO. Securing our sustainment infrastructure is critical to that end. While we should always simplify our processes and procedures, we cannot win against a peer competitor with simple plans. The operational environment requires complex solutions that provide the enemy with multiple dilemmas to solve.The principle of simplicity must not lead us to believe sustainment operations are simple; they are not. Achieving effective sustainment support, where all sustainment requirements (logistics, medical, personnel, and financial) are met, requires inherently complex operations.Maj. Gen. Rodney D. Fogg is the commander of the Combined Arms Support Command and the Sustainment Center of Excellence at Fort Lee, Virginia. He holds master's degrees in logistics management and strategic studies, and he is a graduate of the Quartermaster Officer Basic and Advanced Courses, the Command and General Staff College, and the Army War College.Brig. Gen. Douglas M. McBride Jr. is the 55th Quartermaster General and commandant of the Quartermaster School at Fort Lee. He holds a bachelor's degree in business administration from Northeastern University, a master's degree in resource management from the University of Central Texas, a master's degree in national security and strategic studies from the Naval War College, and a master's degree in strategic studies from the Air University. He is also a graduate of the Ordnance Officer Basic and Advanced courses, the Naval Command and Staff College, and the Air War College.Maj. Graham Davidson is the executive officer for the Quartermaster General at the Quartermaster School. He holds a master's degree in education from the University of Virginia and a master's degree in business with a concentration in supply chain management and logistics from the University of Kansas. He is a graduate of the Quartermaster Officer Basic and Advanced Courses and the Command and General Staff College.