A free Kansas would lead to a free Missouri. A free Missouri would turn into an abolitionist headquarters from which to strike deeper into the South. Financial ruin and a strong chance at racial annihilation would ensue, as to men like Benjamin Franklin Stringfellow and the Platte County Self-Defense Association one simply could not live with black people without holding them as slaves. Maybe the North could get away with its tiny number of free blacks, though Stringfellow doubted it, but the South had vastly more. The abolitionists promised ruin for everyone. Thus
The plan of our Association is not aggressive, but as our name imparts, truly self-defensive. We are pledged diligently to investigate and promptly bring to punishment every violation of the laws which have been enacted for the protection of our slave-property.
One can’t doubt Stringfellow’s sincerity. He does write propaganda informed by a particular time and place not entirely typical of the antebellum South, but he writes with a set of fears very much the same as those expressed by whites living in areas far safer for slavery. The fear that the color line would break and poor whites would turn against slavery informed thinkers in the Lower South just as much as it did those in Stringfellow’s chilly environs. In no state did slaveholders form a majority, though in Mississippi slaveholding households came very close to a majority of white households. They needed the poor whites to see themselves as whites first and so have a common cause with the planter aristocrats, rather than the slaves. The facts of their skin must trump the fact that a black slave and a white freeman doing the same hard farm labor had far more personally in common than the legal walls separating them suggested.
But how could Stringfellow, his Platte County Self-Defense Association comrades, and the slaveholding class in general keep out the threat of class consciousness parting ways with racial consciousness? The Association pledged itself to
We have determined to adopt all proper means to rid ourselves of the free negroes, who are unfit and have no right by law to remain among us: and to prevent all such as are not members of some white family, and subject to their control, from residing in our county.
But sundown towns take us far afield from the Missouri hinterland in 1854. Chasing off free, independently living blacks from Missouri would not keep control of poor whites. For that, the Association had other plans
We have also pledged ourselves to expel from our county all who shall be found proclaiming principles which tend to induce our slaves to escape, to lead them to insurrection and rebellion.
The expulsion, by violence if necessary, of any who spoke out against slavery, in Kansas especially but also at home, gained the Missouri filibusters their place in the history books.