This thesis analyzes the impact that reforms in civil-military relations can have on a military's effectiveness. Specifically, why did reforms undermine military effectiveness in Argentina but not in Chile? To answer this question, this thesis looks at both countries since democratization and parses out both the civil-military reforms carried out as well as changes in effectiveness in an attempt to find linkages between the two. To allow for trend analysis, each country is broken into three discrete blocks of time and analyzed across three independent variablesdecisions not made, resources, and resource allocationin an attempt to determine their impact on the dependent variable: military effectiveness. The two case studies show that while resources and resource allocation are important, their relative importance is unclear since they trended together. The impact of decisions that were not made was inconclusive. As both countries focused on gaining civilian control yet ended in very different positions, this thesis demonstrates the need for the United States to pursue unique policies for each country with which it interacts, based on the needs, desires, and capacities that it possesses.