The dissertation explores the nature of antebellum masculinity and its role in bringing on the American Civil War. It focuses its attention on two crucial episodes of the sectional crisis: the attack on Senator Sumner and the Secession Crisis of 1861 and on the four individuals, Preston Brooks, Charles Sumner, Jefferson Davis and Abraham Lincoln, who played prominent roles in those episodes. Among the issues it explores are the degree to which Northern and Southern ideas of manhood differed and the degree to which Northerners and Southerners associated manhood with sectional identity. Did Southerners associate being a man with being a Southerner and did Northerners associate being a man with being a Northerner? Did Northerners and Southerners view themselves as more manly than their counterparts? What did people expect from their political leaders and how were those expectations shaped by masculinity? Finally, to what degree did political leaders embrace antebellum ideas of masculinity, what influences were they exposed to and how did those influences shape their ideas of masculinity? The biographical profiles illustrate how theoretical notions of masculinity were translated into the experiences of real people. As successful politicians chosen by an exclusively white male electorate, it is reasonable to assume that these individuals were keenly aware of antebellum ideas of masculinity. If nothing else they would have had to at least cater to such ideas to maintain their position. In so doing it demonstrates that 19th century gender roles, and especially 19th century ideas of manhood, played a direct and contributive role in bringing on the sectional crisis and made it inevitable that secession would lead to war. Given the volatile and violent nature of 19th century masculinity, especially that of southerners with its emphasis on honor, violence, and militarism, violent confrontation was not only justified but desirable. In view of such attitudes, war was virtually unavoidable.