This thesis explores the role of political culture in the secession of two Virginia counties: Augusta and Rockbridge. These two counties, which in 1850 were staunchly loyal to the Union, shifted loyalties late in the secession crisis of 1860 and 1861. Comparing local reactions to national politics with local views on the nature and unity of political communities more generally moves the decision to secede in April 1861 into clearer focus. Specifically, comparing regional attitudes towards the sectional controversies surrounding Virginia's constitution with the national debates on slavery in the territories reveals a general concern with the unity of political communities, and the common interests and values needed to sustain such communities. In the context of cross-cutting borderlands between eastern and western Virginia and the northern and southern United States, these sectional questions took on important significance. Political decision-making in this region emerged from a combination of widely-circulating views on the nature of government in this borderland setting. By placing the Valley's secession within these contexts, this thesis argues that Augusta and Rockbridge seceded when they did because events in the North persuaded them that the moral and political character of white northerners had become suspect relative to the question of slavery.