After his nomination he delivered his House Divided Speech, with the biblical reference Mark 3:25, "A house divided against itself cannot stand. I believe this government cannot endure permanently half slave and half free. I do not expect the Union to be dissolved—I do not expect the house to fall—but I do expect it will cease to be divided. It will become all one thing, or all the other."[124] The speech created a stark image of the danger of disunion.[125] The stage was then set for the election of the Illinois legislature which would, in turn, select Lincoln or Douglas.[126] When informed of Lincoln's nomination, Douglas stated, "[Lincoln] is the strong man of the party ... and if I beat him, my victory will be hardly won."[127]
The Senate campaign featured seven debates between Lincoln and Douglas. These were the most famous political debates in American history; they had an atmosphere akin to a prizefight and drew crowds in the thousands.[128] The principals stood in stark contrast both physically and politically. 