Lincoln's convention speech, it will be remembered, declared that in his belief the Union could not endure permanently half slave and half free, but must become all one thing or all the other.

Douglas in his first speech of the campaign attacked this as an invitation to a war of sections, declaring that uniformity would lead to consolidation and despotism.

He charged the Republicans with intent to abolish slavery in the States; said their opposition to the Dred Scott decision was a desire for negro equality and amalgamation; and prescribed his dogma of popular sovereignty as a panacea for all the ills growing out of the slavery agitation.
[Sidenote] Lincoln-Douglas Debates, p.

75.
To this Lincoln replied that Republicans did not aim at abolition in the slave-States, but only the exclusion of slavery from free Territories; they did not oppose the Dred Scott decision in so far as it concerned the freedom of Dred Scott, but they refused to accept its dicta as rules of political action.

He repelled the accusation that the Republicans desired negro equality or amalgamation, saying: "There is a physical difference between the two, which, in my judgment, will probably forever forbid their living together upon the footing of perfect equality; and inasmuch as it becomes a necessity that there must be a difference, I, as well as Judge Douglas, am in favor of the race to which I belong having the superior position.