13. Topic: Thomas Jefferson. Thesis: Thomas Jefferson the "Sage of Monticello" is most often remembered as the primary author of the Declaration of Independence, a document which laid the foundation to a still flourishing and centuries old republic. But despite this great achievement other actions of Jefferson can be interpreted as having a less stabilizing influence on the American experiment in republican-democracy. Jefferson's support of the Virginia and Kentucky resolutions laid the groundwork for the latter Nullification and States Rights concepts, which were used to justify southern session. Also the Louisiana Purchase which greatly increased the American domain contributed first to American expansionism and then sectionalism which in turn lead to southern isolation, another cause of the Civil War. The paradox of Thomas Jefferson was that while making great contributions to the success of the United States his actions also inadvertently put the survival of the union at risk.