To Schuyler Colfax (afterward Vice-President) he said in a letter dated July 6, 1859:
"My main object in such conversation would be to hedge against divisions in the Republican ranks generally and particularly for the contest of 1860. The point of danger is the temptation in different localities to 'platform' for something which will be popular just there, but which, nevertheless, will be a firebrand elsewhere and especially in a national convention. As instances: the movement against foreigners in Massachusetts; in New Hampshire, to make obedience to the fugitive-slave law punishable as a crime; in Ohio, to repeal the fugitive-slave law; and squatter sovereignty, in Kansas. In these things there is explosive matter enough to blow up half a dozen national conventions, if it gets into them; and what gets very rife outside of conventions is very likely to find its way into them."
And again, to another warm friend in Columbus, Ohio, he wrote in a letter dated July 28, 1859:
"There is another thing our friends are doing which gives me some uneasiness. It is their leaning toward 'popular sovereignty.' There are three substantial objections to this. First, no party can command respect which sustains this year what it opposed last. Secondly Douglas (who is the most dangerous enemy of liberty, because the most insidious one) would have little support in the North, and, by consequence, no capital to trade on in the South, if it were not for his friends thus magnifying him and his humbug. But lastly, and chiefly, Douglas's popular sovereignty, accepted by the public mind as a just principle, nationalizes slavery, and revives the African slave-trade inevitably. Taking slaves into new Territories, and buying slaves in Africa, are identical things, identical rights or identical wrongs, and the argument which establishes one will establish the other. Try a thousand years for a sound reason why Congress shall not hinder the people of Kansas from having slaves, and when you have found it, it will be an equally good one why Congress should not hinder the people of Georgia from importing slaves from Africa."
An important election occurred in the State of Ohio in the autumn of 1859, and during the canvass Douglas made two speeches in which, as usual, his pointed attacks were directed against Lincoln by name. Quite naturally, the Ohio Republicans called Lincoln to answer him, and the marked impression created by Lincoln's replies showed itself not alone in their unprecedented circulation in print in newspapers and pamphlets, but also in the decided success which the Ohio Republicans gained at the polls. About the same time, also, Douglas printed a long political essay in "Harper's Magazine," using as a text quotations from Lincoln's "House divided against itself" speech, and Seward's Rochester speech defining the "irrepressible conflict." Attorney-General Black of President Buchanan's cabinet here entered the lists with an anonymously printed pamphlet in pungent criticism of Douglas's "Harper" essay; which again was followed by reply and rejoinder on both sides.
Into this field of overheated political controversy the news of the John Brown raid at Harper's Ferry on Sunday, October 19, fell with startling portent. The scattering and tragic fighting in the streets of the little town on Monday; the dramatic capture of the fanatical leader on Tuesday by a detachment of Federal marines under the command of Robert E. Lee, the famous Confederate general of subsequent years; the undignified haste of his trial and condemnation by the Virginia authorities; the interviews of Governor Wise, Senator Mason, and Representative Vallandigham with the prisoner; his sentence, and execution on the gallows on December 2; and the hysterical laudations of his acts by a few prominent and extreme abolitionists in the East, kept public opinion, both North and South, in an inflamed and feverish state for nearly six weeks.
Mr. Lincoln's habitual freedom from passion, and the steady and common-sense judgment he applied to this exciting event, which threw almost everybody into an extreme of feeling or utterance, are well illustrated by the temperate criticism he made of it a few months later:
"John Brown's effort was peculiar. It was not a slave insurrection. It was an attempt by white men to get up a revolt among slaves, in which the slaves refused to participate. In fact, it was so absurd that the slaves, with all their ignorance, saw plainly enough it could not succeed. That affair, in its philosophy, corresponds with the many attempts, related in history, at the assassination of kings and emperors. An enthusiast broods over the oppression of a people till he fancies himself commissioned by Heaven to liberate them. He ventures the attempt, which ends in little else than his own execution. Orsini's attempt on Louis Napoleon and John Brown's attempt at Harper's Ferry were, in their philosophy, precisely the same. The eagerness to cast blame on old England in the one case, and on New England in the other, does not disprove the sameness of the two things."