Since the Vietnam War, the US Army has struggled with deep cultural issues that have impacted the ability of its leadership to think strategically. In the years following its defeat in Vietnam, the army reestablished its cultural foundations by revamping its doctrine, training, recruiting, professional military education, and equipment with a singular focus on conventional combat. These advances, along with development of advanced information systems and guided munitions, led to victory in the Gulf War, but blinded army leaders as to the larger realm of warfare. The invasion of Iraq seemed wildly successful initially, but senior policy makers assumed peace would follow and turn battlefield triumph into political success. When instead the wars in Afghanistan and Iraq morphed into guerrilla struggles, army leaders were at a loss. Since then, the army has undergone a renaissance of sorts, creating new doctrine and organizations for counterinsurgency warfare and retraining its members to adapt to irregular conflict. It remains to be seen whether these innovations will be permanent, or if the army will slide back into the culturally ingrained mind-set that the only wars worth fighting are large, conventional conflicts. Culture evolves slowly; it remains to be seen whether the army can overcome its anti-intellectual, heroic mind-set in favor of a more balanced mentality.

Culture has enormous influence on military organizations. One can broadly define organizational culture as the assumptions, ideas, norms, and beliefs, expressed or reflected in symbols, rituals, myths, and practices, that shape how an organization functions and adapts to external stimuli and that give meaning to its members. Except in unique circumstances, culture grows slowly, embedding itself so deeply that members often act unconsciously according to its dictates. Because culture lies hidden under more visible organizational doctrine and symbols, one can easily overlook its power. Culture creates organizational identity and establishes expectations of how group members will act. Three important external factors impact military culture: geography, history, and the environment in which navies, armies, and air forces exist. Of all the factors involved in military effectiveness, culture is perhaps the most important. Yet it also remains the most difficult to understand, because it involves so many external factors that distort its formation and continuities, even in different military organizations within the same nation. Organizational culture will shape how military organizations respond to challenges. The hardship is that changing military culture represents an extraordinarily difficult task that may require years, if not decades, to accomplish.

Culture is a key determinant in organizational effectiveness and plays an enormous role in the lives of military organizations. Cultural biases often result in unstated assumptions that have a deep impact on strategy, operational planning, doctrinal creation, and organization and training of armed forces. The impact of culture on military affairs often remains opaque for years, if not decades, after the events it has affected. Leadership is essential to creating and maintaining organizational culture. Leaders who can shape an organization’s culture from its inception have an outsized influence on its future orientation. Leaders, therefore, must be discriminating when establishing the initial culture of an organization, for once embedded, that culture will prove extraordinarily difficult to change. But even superb leaders are limited. Selection of the right subordinate leaders is critical if an organization’s culture is to survive a leadership transition. Some military organizations do change, assisted by cultures that embrace innovation and a reasonable degree of risk-taking. Organizational culture takes on the characteristics of wider societal culture, but when the military becomes a caste apart, the result can be the degradation of its ethical foundations. Military organizations often have subcultures with significant influence on the larger organization. Technology-centric forces must not allow a culture focused on technological excellence to turn into one centered on technological determinism. Professional military education is critical in sustaining organizational culture.

The American Civil War presented an exceptional state of affairs in modern warfare, because strong personalities could embed their own command philosophies into field armies, due to the miniscule size of the prior US military establishment. The effectiveness of the Union Army of the Tennessee stemmed in large part from the strong influence of Ulysses S. Grant, who as early as the fall of 1861 imbued in the organization an aggressive mind-set. However, Grant’s command culture went beyond simple aggressiveness – it included an emphasis on suppressing internal rivalries among sometimes prideful officers for the sake of winning victories. In the winter of 1861 and the spring of 1862, the Army of the Tennessee was organized and consolidated into a single force, and, despite deficits in trained personnel as compared to other Union field armies, Grant established important precedents for both his soldiers and officers that would resonate even after his departure to the east. The capture of Vicksburg the following summer represented the culminating triumph of that army, cementing the self-confident force that would later capture Atlanta and win the war in the western theater.