[Buchanan’s] understanding of the way politics worked, of the function of political parties, of the nature of the Union and the policies needed to preserve it were inculcated through a party system that rewarded him with increasingly powerful positions and influence…The Democratic Party came to represent, in his eyes, the Union itself; it was a coalition of free and slave interests whose survival depended on the suppression of sectional conflict. The driving force of the Democratic Party had always been the preservation of the Union and, indeed, the party could not survive in its present form without sectional tensions that it could direct to its own purposes. Ever since the creation of the party, sectional pressures welled up from its Northern and Southern wings; the party effectively contained these pressures at the state level, permitting its leaders to use sectional fidelity as a test of party loyalty without carrying it into the national convention. As sectional issues became more acute in the late 1840s and broke into the national organizations with the advent of the territorial question, politicians like Buchanan resorted to familiar methods to limit the damage. Buchanan supported the extension of the Missouri Compromise line to the Pacific and opposed popular sovereignty as the party’s program. By the time that he entered the White House, Buchanan was already fully trained in the system’s strategy for handling sectional questions. Firmly believing, along with most politicians of his generation, that slavery’s ultimate fate was beyond the reach of ordinary politics, Buchanan saw only mischief and peril in the agitation of the issue.