Republicanism, a long-standing ideology, which embodied political liberty, virtue, and constitutional law, shaped America’s political culture from the country’s inception. The Republican Party’s formation in the 1850s was no exception to this rule. Paying close attention to the social and political climate in Massachusetts, this thesis will journey through the United States’ turbulent antebellum years and examine how the abolitionist organization known as the Boston Vigilance Committee (BVC) fashioned the contours of this anti-slavery party. Although scholars debate the committee’s origins, by 1846 members increased and expanded their activism in protecting escaped slaves from being returned to slavery and in assisting fugitives to freedom. By standing on moral, economic, and legal ground, Vigilance Committee members transformed Boston’s political culture and helped mobilize Northern support for an anti-slavery agenda that founded the Republican party and ultimately culminated in slavery’s eventual demise. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection