Northern White Supremacist and Disunionists
The Republican party platform in 1860 opposed the expansion of African slavery into the territories, keeping those areas open to white settlement only. President James Buchanan of Pennsylvania was by no means a Southern fire-eater – but he clearly saw the movement toward disunion coming once again from the North, and placed the blame for the secession crisis at the feet of the extremist abolitionists who only saw (and demonstrated in Kansas) a future of fire and blood.
Bernhard Thuersam, Chairman
North Carolina War Between the States Sesquicentennial Commission
"The Official Website of the North Carolina WBTS Sesquicentennial"
Northern White Supremacists and Disunionists:

[James] Buchanan wished that he could feel…optimistic in regard to the situation in Kansas. The trial of popular sovereignty had brought civil war to that territory. Settlers had gone there to claim land and fight for political control. New Englanders, because of better organization and financing back home, came in greater numbers and with more armament than the Southerners, but the latter had the sympathy of the Missourians who cast ballots for the first Kansas territorial legislature and elected candidates favorable to the South.  The New Englanders called the invaders “border ruffians,” but they do not appear to have been very different from any of the frontier inhabitants of their day.
When [President Franklin] Pierce removed Kansas Governor Andrew H. Reeder, for fraudulent dealings in land, the antislavery men charged that he had been fired for denouncing the territorial election. The free State men set up a legislature of their own at Topeka, elected Reeder as Constitutional representative, and drafted [the LeCompton] constitution.   This, incidentally, was an anti-Negro rather than anti-slavery constitution; it established white supremacy by forbidding any Negroes to live in Kansas.
About 11 p.m. of May 24 [1854], John Brown, his three sons, and four henchmen headed for Pottawatomie Creek in Kansas and later knocked at the door of James Doyle, a Southerner whom none of the party had ever seen before. Doyle, half-dressed and unarmed, asked them to come in, but Brown’s men drew pistols and invited him to come out. When Doyle’s sons, William, aged 22, Drury, aged 20, and John, 16 stepped to their father’s side, Brown ordered them to come along. A few minutes later Mrs. Doyle and her youngest son, who had remained with her, heard screams and pistol shots outside the cabin, and then there was silence.
After midnight Allen Wilkinson, who was up late because his wife Louisa was sick with measles, went to answer a thunderous pounding on the door. “In the name of the Northern Army, open up,” came a deep voice. Brown’s party entered and ordered Wilkinson outside.
Not until the next morning did anyone dare go out and investigate. James Doyle and two of his sons lay near the cabin, with bullets through their heads, their skulls split in two with a broadaxe, their sides hacked open, and their fingers cut off. A neighbor found Allen Wilkinson shot in the head, his skull chopped apart and his side pierced. [Antislavery] extremists hailed Brown as a hero. Slavery was a sin, and the wages of sin was death. God had ordained Brown to smite the wicked.
The Republicans named [in 1860] John C. Fremont [for president and the] Republican platform promised to promote the building of a railroad to the Pacific, to make big appropriations for rivers and harbors, and to prohibit in the territories “those twin relics of barbarism, polygamy and slavery.”  If they were victorious, the platform pledged to arrest, jail, and possibly execute those who disagreed with them on Kansas.
Fremont did not worry [Democrat Buchanan]; the real issue was the Republican threat of disunion and civil war.  Buchanan stated the keynote of his campaign in these words, “The Union is in danger and the people everywhere begin to know it. The Black Republicans must be, as they can be with justice, boldly assailed as disunionists, and this charge must be reiterated again and again.”
Ohio’s [Republican] Representative Joshua Giddings had announced “I look forward to the day when there shall be a servile insurrection in the South; when the black man…shall assert his freedom, and wage a war of extermination against his master; when the torch of the incendiary shall light up the towns of the South…I will hail it as the dawn of the millennium.” New York’s Governor William H. Seward asserted that “there is a higher power than the Constitution.”  A group of Republicans petitioned Congress to take “measures for the speedy, peaceful, and equitable dissolution of the existing union.”  [New York Times founder and publisher Henry] .L. Raymond told an audience at Faneuil Hall, “Remembering that he was a slaveholder, I spit upon George Washington.”
(President James Buchanan, A Biography, Philip S. Klein, American Political Biography Press, 1962,  pp. 249-258)