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.

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.