Self Defensive Association.—The great number of free-state settlers that came into Kansas territory in 1854 began to alarm the friends of slavery, who saw that it would be practically impossible legally to compete with the heavy tide of emigration from the east. The people of northwest Missouri had been led to believe that the prospects of slavery in Kansas were good, but this idea was overthrown by the coming of such great numbers of what the Missourians called "northern cattle." The advocates of slavery were disappointed but not discouraged, and attempted to terrify the new settlers by threats and persecutions. The pro-slavery publications represented the emigrant aid societies as gathering the paupers of the great cities in the east and hiring them to come to Kansas to disturb the institutions of Missouri. As a result of the sentiment thus aroused, meetings were held in some of the towns in western Missouri. This agitation led to the formation on June 15, 1854, of the Platte County Self-Defensive Association. The constitution of this organization contained a preamble and nine articles, the substance of which was that all free negroes must be expelled from the country; no traffic was to be allowed between whites and slaves; no slaves were to be allowed to hire their own time; the association was to try to punish all abolitionists; and the members pledged themselves to bring any guilty to immediate punishment. Nearly 1,000 persons signed this constitution. In reality the association was an immense lynch court, consisting of six judges and 1,000 detectives, as each member acted in that capacity. There was absolutely no appeal from the decision of a judge and any two members.

At the first meeting of the association the following resolutions were passed: "That we, the members of the Platte County Self Defensive Association, do solemnly pledge ourselves to go at the call of our brethren, who are across the river in Kansas, and drive out from their midst the abolition traitors." Thomas A. Minard, formerly a sheriff in Iowa, a man of good character and wealth, had come to Kansas and was building a home. He was known to have declared his intention to vote for Kansas to become a free-state. Members of the association arrested him, he was tried before the lynch court, condemned as an abolitionist, ordered to leave the country within 24 hours or receive 50 lashes on his bare back, and was driven from his home with a sick family, into the unsettled wilderness. An old white haired man was seized upon the testimony of a negro, condemned as an abolitionist and given 48 hours in which to leave the country or receive 50 lashes on his bare back. The association did not stop with trying abolitionists, but tried to force the inhabitants to trade only with those who favored slavery and to force the merchants to purchase in slave holding communities. It is believed that members of this association were among the pro-slavery men who attempted to intimidate and drive the free-state settlers from Lawrence, which proved unsuccessful. The work of the association became so intolerant that these actions proved its undoing, for the citizens of Weston called a public meeting at which resolutions were adopted in which they declared that the residents were competent to decide who should be expelled from the community and that mob law could be tolerated no longer. In the resolutions the citizens disclaimed the action of the association. Thus ended the power and history of the Self-Defensive Association.