Why do the combat capabilities of individual soldiers vary so much? This book seeks to provide an answer to this and other questions about variability in combat performance. Some soldiers flee quickly from the battlefield, while others endure all hardships until the bitter end. Some combat units can perform numerous types of missions, while others cannot keep themselves organized during peacetime. Some militaries armed with obsolete weapons have out fought enemies with the latest weapons, just as some massively outnumbered armies have beaten back much larger opponents. In this first social scientific study of the effectiveness of combat troops, Newsome evaluates competing explanations for the varying combat capabilities and performances.

There are four main explanations, each emphasizing the influence of a single factor. The first focuses on material endowments. How well funded are the troops? Do they have the latest protective gear and the most advanced weaponry? Second, some analysts claim that democracies produce better commanders, superior strategies, more motivated personnel, or better-managed personnel; others, however, associated those characteristics with more authoritarian forms of government. Third is the idea that giving more power to the troops on the ground in individual combat units empowers them with decision-making capability and adaptability to fast-changing situations and circumstances. Newsome presents evidence that decentralized personnel management does correlate with superior combat performance. Fourth, soldier capabilities and performance often are assumed to reflect intrinsic attributes, such as prior civilian values. Newsome argues that the capabilities of combat soldiers are acquired through military training and other forms of conditioning, but he does not entirely discount the role of a soldier's individual character. In the age-old nature vs. nurture argument, he finds that intrinsic qualities do count, but that extrinsic factors, such as training and environment, matter even more.