The book seeks to determine the degree that nationalism played as acontributing factor in the American Civil War. The United States currently applies analytic and diagnostic frameworks to potential hotspots around the globe in order to determine their likelihood or potential for violence. Foreign policy and preventive measures are shaped by the predictions of these diagnostic tools. What prognosis would they bare if used in retrospect onthe American Civil War? Would they indicate the war as being inevitable or unnecessary? The answer to these questions is based largely on the causal link between certain nationalism movements and their potential risk for violence. I propose to answer these questions and the -why civil war?" question using the analytic tool developed by Stephen Evera.Many view the American Civil War as inevitable while others propose it was anunnecessary tragedy. How do we answer the question, -why a civil war?" We can answer this question subjectively or through a more scientific process. The debate over a more scientific study forms the problem background and significance of my study. It is my hypothesis that the issue of nationalism greatly impacted the risk of war. Stephen Van Evera, a political scienceteacher at M.I.T., makes a strong case for the causal link between nationalism and war. I will explain and use Evera's two part analytic framework of "immediate/proximate causes' and the three underlying catalytic factors of the immediate/proximate causes' (structural, political/environmental and perceptual factors) as an assessment tool. I will apply this analyticframework or tool to the federal and the southern/Confederate nationalist movements. This analysis will explain the conditions that cause certain nationalist movements to escalate to violence and it will offer judgement on the role nationalism played in the escalation between north and south. Finally, we'll address the question of how, if at all, can the war causingattributes of nationalism be suppressed or neutralized? Were these remedies attempted prior to violence erupting between north and south and what were the results? Could the American Civil War have been averted? We'll use Evera's framework to answer these concluding questions and come up with a "scientific' conclusion.My methodology involves research via the AU library, Internet and personal contacts with course instructors in the history departments of AWC and ACSC.The structure of the paper will follow a diagnosis-solution pattern. The paper will be organized as follows. First, I'll introduce the hypothesis and raise the significant questions. Second, the main body will define and apply Stephen Evera's analytic checklist to the historical facts of the American Civil War. Third, the preventive measures will be introduced and explored as they relate to circumstances and actual efforts taken by northern and southern leadership prior to the outbreak of violence/war. Was the war avoidable or inevitable? Finally, there will be discussion and anticipated results followed by conclusions and possible lessons learned..