What was at stake in the 1858 debate between Abraham Lincoln and Stephen A. Douglas was a U.S. Senate seat from Illinois. The seven debates were conducted for the most part in the central area of Illinois between St. Louis and Rock Island, where political allegiances were most divided and hard to identify.
To Douglas the chief aim of the nation should be to expand its borders and its institutions, to extend the area of freedom for whites. If slavery were carried into new territories as part of the process, that was a local matter, rather the same as permitting the manufacture and sale of liquor was a local matter. The morality of slavery to Douglas was a matter of local option, though he probably was personally opposed to the institution. But to Lincoln the immorality of slavery was absolute, and such an absolute ought to rule in legislating for a new country like Kansas, where slavery had not existed before. "I belong to that class," he said "who contemplate slavery as a moral, social and political evil." And Douglas, said Lincoln in the most memorable line of the Galesburg debate, was "blowing out the moral lights around us when he maintains that anyone who wants slaves has a right to hold them."
The terrible weather on October 7, 1858 brought the debate to the shelter of the east side of Knox College's main building from the park where it had been scheduled. Accounts vary but newspapers reported that 10,000 people attended the debate.