The Two Armies : Adaptation, Durability, and the United States Army and National Guard

The United States maintains two distinct armies: an active duty, or force under federal control, and a National Guard nominally under state control with the option of being federalized. This bifurcation of the American military remains largely unchanged since the nation's founding. Given the inclination of policymakers to centralize power under conditions of existential threat or disaster, this continued division of the armed forces is puzzling. What explains the durability of the two armies and their ability to adapt to new or qualitatively different roles over time? This paper develops a conceptual framework that seeks to explain agency adaptation and durability. I theorize that when faced with new or qualitatively different demands from policymakers, agencies bargain with their overseers for resources and institutional changes that facilitate adaptation and mitigate stressors. The agency's political environment, particularly institutional arrangements and ideational factors, mediates agency adaptation by expanding or curtailing an agency's range of response, further influencing the nature of the principal-agent bargain. I briefly consider cases that illustrate this conceptual framework as it relates to the durability of the two armies and propose avenues for future research