In the end, the Jeffersonian synthesis between northern freedom and southern power proved resilient in the face of sectional crisis. The Democratic-Republican coalition fractured in the 1820s, but it soon reformed in a new guise under the iconic leadership of Andrew Jackson. The Missouri Crisis indicated the potential influence of antislavery nationalism, but it also confirmed the ongoing political power of slaveholders in the American nation-state. Thus in some respects it was a crisis of meaning as much as a crisis of policy. As northerners and southerners fought over the expansion of slavery and the admission of Missouri, a more obscure conflict took place over the nature of the Jeffersonian coalition, and the legacy of past reconciliations between freedom and slavery. In attempting to articulate a foundational antislavery nationalism, northerners were struggling not only with slaveholders in the American Congress, but also with themselves. [my emphasis]Riley also talks about how the Missouri crisis and the Compromise that resolved it reflected the fundamental contradiction between democracy and chattel slavery:
Traditionally seen as the opening act in the long antebellum conflict over slavery in the United States, the Missouri Crisis also marked the culmination of sectional conflict over slavery during the Jeffersonian era. For northern Republicans, the Crisis was a referendum on Jeffersonian democracy, as they found themselves confronting, with more clarity than ever before, some of the central dilemmas of their ideological and partisan past. How would they respond to the power of slaveholders in their political coalition, especially when it came to making national-level, democratic decisions about slavery? Would they defend universalist conceptions of citizenship and democracy on behalf of free African Americans or would they continue to draw racial lines around democratic freedom? Would they continue to tolerate southern bondage in defense of their own freedom?Riley also argues that Republicans, including Thomas Jefferson and Andrew Jackson, were mistaken in seeing Federalists and the specter of the Hartford Convention in the antislavery arguments over the Missouri crisis. He argues that the impulse came more from northern Republicans who were starting to put a higher priority on the democratic side of their political heritage than on the part that defended slavery. But Jefferson himself didn't seem to have made much distinction between the two. That is, he thought that at least some of the antislavery Republicans were closet Federalist. By the mid-20s, what is sometimes called the second American party system was developing, with sharp differences between the John Quincy Adams National Republicans and the Jacksonian Republicans, who took to calling themselves Democrats, the name the party still uses.
Northern Republicans answered these questions ambivalently, leaving a complicated legacy for the antebellum period. Their resistance to slavery extension foreshadowed the moderate antislavery politics of a very different Republican party in the 1850s. Yet they retained many of the key symbols and concepts of Jeffersonian politics, and they rarely questioned the relationship between slavery and democracy that had allowed southern bondage to expand alongside northern freedom in the early republic. [my emphasis]