Many eastern Republicans believed that in this emergency Illinois Republicans should support Douglas, or at least that they should do nothing to diminish his chances for reelection; but Illinois Republicans decided otherwise and nominated Abraham Lincoln as their candidate for the senatorship.

Then followed the memorable Lincoln-Douglas debates.
This is not the place for any extended account of the famous duel between the rival leaders, but a few facts must be stated.

Lincoln had slowly come to the perception that a large portion of the people abhorred slavery, and that the weak point in the armor of Douglas was to be found in the fact that he did not recognize this growing moral sense.
Douglas had never been a defender of slavery on ethical grounds, nor had he expressed any distinct aversion to the system.

In support of his policy of popular sovereignty his favorite dictum had been, "I do not care whether slavery is voted up or voted down." This apparent moral obtuseness furnished to Lincoln his great opportunity, for his opponent was apparently without a conscience in respect to the great question of the day.

Lincoln, on the contrary, had reached the conclusion not only that slavery was wrong, but that the relation between slavery and freedom was such that they could not be harmonized within the same government.