In 1858 there was a Senate Race in Illinois between Abraham Lincoln and Stephen Douglas. At the time, Stephen Douglas was the incumbent, but in an attempt to take Douglas’s seat, Lincoln challenged Douglas to a series of debates.

Although the exact format of the debates was slightly different than the Lincoln-Douglas of today (back then the first speaker spoke for 60 minutes, the second had a 90-minute rebuttal, and then the first speaker had a 30-minute rebuttal/time for closing arguments) the basic premise of the debates between Lincoln and Douglas are the same as LD debates today.