Abolitionist activism in 1850's America was divided among two groups of thought: disunionists, who understood the American Constitution to be a pro-slavery document, and political abolitionists, who believed the Constitution was antislavery. This paper traces the origins and structures of each argument, specifically focusing on the philosophies of Frederick Douglass and William Lloyd Garrison. It supplements their views with the works of other prominent abolitionists such as Lysander Spooner, Wendell Phillips and Gerrit Smith. In analyzing their rhetoric and beliefs, this paper examines the core of the contention between disunionists and political abolitionists and asserts that the chief divide between the two groups involved questions of whether the wording of the Constitution supported slavery, whether the drafters of the Constitution intended the document to condone slavery, and whether the intentions of the Constitution could be divorced from its interpretation at the hands of the American government and public. Furthermore, this paper argues that the conflict between disunionists and political abolitionists is not confined to the pages of history. It makes parallels between modern activism and the abolitionist writings of the 1850's, attempting to show that the same anti-Constitution reasoning of the disunionists permeates many present-day activists and scholars. It presents Frederick Douglass, Wendell Phillips and Gerrit Smith as proponents of a philosophy of radical constitutionalism which supports legal and cultural reform grounded in a respect for the ideals they believed were embedded within the Constitution and the Declaration of Independence. This paper advocates constitutional radicalism as the most just and effective method of American reform, echoing Douglass in his faith in American idealism and the power of law and civic duty to promote national justice.