David Herbert Donald, Lincoln (New York: Touchstone, 1996), 209.
Thus the three sections of Lincoln’s house divided speech had the inevitability of a syllogism: The tendency to nationalize slavery had to be defeated. Stephen A. Douglas powerfully contributed to that tendency. Therefore, Stephen A. Douglas had to be defeated. Attracting national attention, Lincoln’s house-divided speech sounded very radical. Advanced five months before William H. Seward offered his prediction of an “irrepressible conflict” between slavery and freedom, it was the most extreme statement made by any responsible leader of the Republican party. Even [William Henry] Herndon, to whom Lincoln first read it, told his partner: “It is true, but is it wise or politic to say so?" As the editor John Locke Scripps explained, many who heard or read Lincoln’s speech understood it as “an implied pledge on behalf of the Republican party to make war upon the institution in the States where it now exists.” Aware that his house-divided prediction was controversial, Lincoln in the months ahead tried to blunt its impact, telling Scripps “that whether the clause used by me, will bear such construction or not, I never so intended it.” In this passage, he insisted, “I did not say I was in favor of anything…I made a prediction only – it may have been a foolish one perhaps.” But he never disavowed it; he knew it was the necessary first premise in his syllogism proving that Douglas should be defeated.