The dissertation argues that the United States Army was a slaveholding institution. It explains how the military, the central instrument of statecraft in the 19th century, evolved as a national establishment while condoning and promoting slavery in its ranks. An empirical study of often ignored military pay records reveals that from the army’s foundation to the abolition of slavery, thousands of enslaved people served as officers’ servants and became integral to the military. In 1816, Congress authorized allowances, rations, and clothing for officers’ private servants while prohibiting the former custom of taking soldiers as servants. By reimbursing officers who held or hired enslaved servants, Congress not only sanctioned slavery but also subsidized and created incentives for officers to own, utilize and trade enslaved people. The dissertation shows that over three-quarters of officers, southerners and northerners alike, held slaves as servants during their military careers. Over 9,000 enslaved people were forced into the army, nearly three times more than the number of officers. The dissertation investigates the origins and scope of slavery within the army, the legal, fiscal, and violent mechanisms that sustained it, and the profound impact slavery had on the American military establishment. By analyzing the U.S. Army, the most dominant national establishment, as a slaveholding institution, this project adds to the expanding literature on the “slaveholding republic.” The dissertation goes beyond merely illustrating “slave power” in the federal army by offering a ground-level investigation into how slavery got its foothold in an important national organization. Virtually unnoticed by prior historians, some 180,000 payrolls in the National Archives reveal the mundane realities of enslaved military servants and their enslavers. Each document included servants’ names, physical descriptions, locations, and allowances paid for their subsistence. The dissertation utilizes an original database of thousands of payrolls identified, sampled, and digitized, particularly for this project. The database has over two million data points, which enable grasping the phenomena of military slavery and tracking down individual servants’ and enslavers’ trajectories. The data shows that officers carried enslaved servants wherever they went, regardless of local laws forbidding it – even in so-called “free states” in the continental United States, Mexico, and Europe. Nearly 13% of all officers’ pay expenses went directly to subsidize slavery. Ratio analysis demonstrates that the bureaucracy and funding mechanisms that evolved before 1816 kept enslaved servitude stable. Thus, until the Civil War (1861-1865) and the unmaking of slavery, the army – which expanded and protected the frontiers of an empire in the making – not only benefited from the slave market but was a significant force in its expansion. Moreover, permitting and subsidizing slavery in the army made the U.S. government complicit in its brutalities, including forced removals, human trafficking, and the separation of families. Military slavery developed gradually with the foundation, bureaucratization, and professionalization of an American military peace establishment. It evolved from 1797 to 1816 through competing policy objectives, resulting in an enduring bureaucratic (and euphemistic) workaround: “servants not soldiers.” Facing public criticism over officers’ abuse of soldiers’ labor, the army gradually “outsourced” officers’ servants through a dual process of privatization and racialization of military labor, differentiating between “public” and “private” service; between free, white soldiers and enslaved, black servants. Though serving slaveholders’ interests, the adopted solution of “Servants not soldiers” was a product of bureaucratic contingencies and ad-hoc decision-making and not a top-down policy orchestrated by a cabal of enslavers. Interestingly, a simple, basic question of reimbursement led somewhere perhaps unanticipated, ending in government-sponsored enslaved servitude. To add this level of contingency is not to make excuses, not to pose something akin to an “unthinking decision,” but to make us aware of the degree to which “the problem of slavery” was most frequently “solved” by accommodating it institutionally, rather than contesting it politically or morally. Thus, the dissertation illuminates an often-ignored aspect of the United States as a “slaveholding republic.”