It may be useful, as a descriptive prelude to analysis, to divide the modern national state in the United States into broad functional categories - social welfare, economic growth/regulation, and national security. Scholars of American political development have proceeded from this point of departure to explore the developmental trajectory of each category. However, although the descriptive move to separate state functions may work for the modern era (that is, from the beginning of the twentieth century to the present), it is more problematic when we turn to the early national period. For the first hundred years after the Constitution, national security and economic development were closely connected. By extension, the executive branch, thru its control of the military, was more involved in economic tasks associated with territorial expansion and consolidation than the standard depiction of the "weak" traditional presidency would suggest. We propose in this paper to reexamine the role played by the national security state during the early national period in promoting economic expansion, focusing in particular on the political mechanisms that linked the military role to expansionist objectives.Both historians and APD scholars have puzzled over military-political linkages in the 1789-1900 period. Among the former, Robert G. Angevine recently has argued that the army played an important role in the development of public infrastructure from the earliest days of the republic. But military leaders often found themselves at odds with political leaders because each group was driven by different calculations. Where the former understood infrastructure investment as a solution to the collective goods challenge of national security - transportation was necessary to allow the army to move its very modest resources to a point of danger - the latter construed expenditures on public works as a distributive benefit that could be exploited for partisan gain. Among political scientists, Christopher McGrory Klyza has described a number of roles played by specialized branches of the army (such as the engineers and the topographical engineers) to promote economic development where private wherewithal proved insufficient. Put another way, his account reveals a military that could be used to solve classic collective goods problems.We seek to build upon this literature to explore our working hypotheses: (1) The army played a pivotal role in national economic development in the early republic by meeting a succession of collective goods shortages. (2) Recognizing the economic importance of the army, politicians sought to subordinate it to their partisan political imperatives. (3) The executive branch served as the key conduit between politicians and the army, translating the priorities of the former into the orders for the latter. (4) The War Department, and in particular the Secretary of War, became a key actor in economic development because the chief executive lacked the political and institutional capacity to manage routine peacetime army operations. (5) Features of the early partisan executive branch, notably limited presidential control over cabinet appointments, facilitated the integration of elite interests and military policy into what might be termed "the cavalry-railroad complex." ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]