Douglas W. Jaenicke, "The Rupture of the Antebellum Democratic Party: Prelude to Southern Secessions from the Union," Party Politics , 1 (July, 1995), 347-367.

First Paragraph:
In 1860, differences over the status of slavery in the territories of the USA ruptured the national Democratic Party with the result that two national Democratic organizations competed for Democratic votes in the presidential election. At the time, politicians and newspaper editors declared that the southern Democrats' defection from the national party foreshadowed southern secession from the Union. Illinois Senator Stephen Douglas, acknowledged leader of the northern Democrats and Democratic presidential nominee, warned:'Secession from the Democratic party means secession from the federal Union' (Johannsen, 1973: 772). Agreeing, the Richmond Examiner rhetorically inquired: 'If the union between the democracy of the North and of the South is dissolved in...1860, how long will the Union of the States be likely to continue?' The historian Don Fehrenbacher (1978: 538) concurs with these contemporary assessments: 'the Democratic conventions [at Charleston and Baltimore] were rehearsals for secession'. Paradoxically, the internal conflict within the national Democratic Party provides a new perspective on secession, not because it reproduced the wider national disagreement about slavery, but precisely because it was so much narrower than that national conflict.

Figures and Tables:
Figure 1: Attitudes towards and partisan positions on slavery.

Last Paragraph:
Both defection from the party and secession from the Union indicated the impossibility of sustaining a procedural consensus in the absence of underlying substantive agreement. However, the rupture of the Democratic Party rather than the disruption of the Union better illustrated this truth because the Democrats, not the Republicans, struggled to maintain a procedural consensus in the face of a disagreement over slavery. While southern secession from the Union followed anti-slavery's overt victory in the presidential election, the southern defection from the Democratic Party occurred despite its attempt to sustain a procedural accord in the face of substantive disagreement. Therefore, precisely because northern Democrats successfully resisted addressing the substance of the slavery issue prior to, during and even after the Civil War, the disruption of the Democratic Party with its self-consciously procedural northern wing, not southern secession from a Union dominated by anti-slavery Republicans, better confirms that a procedural consensus cannot be sustained in the face of substantive disagreement.